U.S. patent application number 17/829180 was filed with the patent office on 2022-09-15 for prohemostatic proteins for the treatment of bleeding.
The applicant listed for this patent is Academisch Ziekenhuis Leiden. Invention is credited to Mettine H. A. Bos, Pieter H. Reitsma, Daniel Verhoef.
Application Number | 20220288172 17/829180 |
Document ID | / |
Family ID | 1000006366463 |
Filed Date | 2022-09-15 |
United States Patent
Application |
20220288172 |
Kind Code |
A1 |
Verhoef; Daniel ; et
al. |
September 15, 2022 |
PROHEMOSTATIC PROTEINS FOR THE TREATMENT OF BLEEDING
Abstract
Described are recombinant FXa polypeptides that can be used as
antidotes to completely or partially reverse an anti-coagulant
effect of a coagulation inhibitor in a subject, preferably a direct
factor Xa inhibitor. Disclosed herein are recombinant factor Xa
proteins and a method of completely or partially reversing an
anti-coagulant effect of a coagulation inhibitor in a subject.
Inventors: |
Verhoef; Daniel; (Leiden,
NL) ; Reitsma; Pieter H.; (Leiden, NL) ; Bos;
Mettine H. A.; (Leiden, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Academisch Ziekenhuis Leiden |
|
|
|
|
|
Family ID: |
1000006366463 |
Appl. No.: |
17/829180 |
Filed: |
May 31, 2022 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
16719866 |
Dec 18, 2019 |
11357836 |
|
|
17829180 |
|
|
|
|
15313881 |
Nov 23, 2016 |
10537618 |
|
|
PCT/NL2015/050377 |
May 26, 2015 |
|
|
|
16719866 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07K 14/46 20130101;
C07K 2319/00 20130101; A61K 38/4846 20130101; C12N 9/6432 20130101;
C12Y 304/21006 20130101 |
International
Class: |
A61K 38/48 20060101
A61K038/48; C12N 9/64 20060101 C12N009/64; C07K 14/46 20060101
C07K014/46 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2014 |
EP |
14169895.1 |
Claims
1. A recombinant protein comprising: a coagulation factor Xa
polypeptide having an alteration in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-289
and Asp-320 of SEQ ID NO: 1, wherein the alteration is an insertion
of from 1-50 amino acid residues.
2. The protein of claim 1, wherein the insertion is combined with a
replacement of between 1-8 amino acid residues in the region of
amino acid residues between Gly-289 and Asp 320 of SEQ ID NO:
1.
3. The protein of claim 1, wherein the insertion is in the region
of amino acid residues between His-311 and Asp-320 of SEQ ID NO:
1.
4. The protein of claim 3, wherein the replacement is in the region
of amino acid residues between His-311 and Asp-320 of SEQ ID NO:
1.
5. The protein of claim 1, wherein the insertion is from 1-20 amino
acid residues.
6. A pharmaceutical composition comprising: the protein of claim 1
or a pharmaceutically acceptable salt thereof, and a
pharmaceutically acceptable carrier.
7. The pharmaceutical composition of claim 6, further comprising
one or more of diluents, fillers, salts, buffers, stabilizers, and
solubilizers.
8. The pharmaceutical composition of claim 6, wherein the
pharmaceutical composition is encapsulated.
9. The pharmaceutical composition of claim 6, wherein the
pharmaceutical composition is in the form of a cream, foam, gel,
lotion, or ointment.
10. The pharmaceutical composition of claim 6, wherein the
pharmaceutical composition is in an injectable or infusible
form.
11. The pharmaceutical composition of claim 6, wherein the carrier
is an aqueous or oily solution, dispersion, emulsion, and/or
suspension.
12. The pharmaceutical composition of claim 6, wherein the carrier
is distilled sterile water, saline, buffered saline, or another
pharmaceutically acceptable excipient for injection.
13. The pharmaceutical composition of claim 6, configured for use
as a bypassing agent in the treatment or amelioration of a disorder
wherein normal blood coagulation is impaired.
14. A method of completely or partially reversing an anti-coagulant
effect of a direct factor Xa inhibitor in a subject, the method
comprising: administering to the subject an amount of the protein
of claim 1, wherein the amount of the protein is sufficient to at
least partially reverse the anti-coagulant effect of the direct
factor Xa inhibitor in the subject.
15. A method of at least partially reversing an anti-coagulant
effect of a direct factor Xa inhibitor in a subject, the method
comprising: administering to the subject the pharmaceutical
composition of claim 6 so as to at least partially reverse the
anti-coagulant effect of the direct factor Xa inhibitor in the
subject.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of pending U.S. patent
application Ser. No. 16/719,866, filed Dec. 18, 2019, U.S. Pat. No.
11,357,836 (Jun. 14, 2022), which is a continuation of copending
U.S. patent application Ser. No. 15/313,881, filed Nov. 23, 2016,
now U.S. Pat. No. 10,537,618, issued Jan. 21, 2020, which claims
the benefit under 35 U.S.C. .sctn. 371 of International Patent
Application PCT/NL2015/050377, filed May 26, 2015, designating the
United States of America and published in English as International
Patent Publication WO 2015/183085 A1 on Dec. 3, 2015, which claims
the benefit under Article 8 of the Patent Cooperation Treaty to
European Patent Application Serial No. 14169895.1, filed May 26,
2014, the contents of the entirety of each of which are hereby
incorporated by this reference.
TECHNICAL FIELD
[0002] This disclosure is in the field of medical treatment. In
particular, the disclosure is in the field of treating, preventing
or ameliorating bleeding complications resulting from a modulated
hemostatic response.
BACKGROUND
[0003] Millions of patients worldwide require anticoagulant drugs
for the prophylactic management of stroke in atrial fibrillation or
prevention and treatment of venous thrombosis. Prophylaxis is
traditionally centered on the coumarin-based oral anticoagulant
Vitamin K Antagonists (VKAs) such as Warfarin, Acenocoumarol and
Phenprocoumon, which block the synthesis of vitamin K-dependent
blood coagulation factors. Further anticoagulant drugs include
target-specific anticoagulants, such as dabigatran, that inhibit
the enzyme thrombin, which is a serine protease that converts
soluble fibrinogen into insoluble strands of fibrin. Efficacious
reversal of the anticoagulant effect, with a so-called antidote, is
a prerequisite for safe drug usage. This is particularly important
considering that, just in the Netherlands alone, over 10,000
patients treated with anticoagulants annually suffer from an
adverse severe bleeding event, including up to 2,000 fatalities (H.
Adriaansen, et al., "Samenvatting Medische Jaarverslagen van de
Federatie van Nederlandse Trombosediensten," 2011; 1-44).
[0004] Currently available anticoagulant-antidote pairs to prevent
over-anticoagulation are heparin-protamine and warfarin-vitamin K.
Prothrombin complex concentrates (PCC) containing vitamin
K-dependent coagulation factors II, IX, X (3-factor PCC) or II,
VII, IX, X (4-factor PCC) and varying amounts of proteins C and S
have been indicated for the reversal of warfarin-related effects
(see, for example, Frumkin, Ann. Emerg. Med. 2013, 62:616-626).
Fresh frozen plasma and recombinant factor VIIa (rfVIIa) have also
been used as non-specific antidotes in patients under low molecular
weight heparin treatment, suffering from major trauma or severe
hemorrhage (Lauritzen et al., Blood 2005, 106:2149, Abstract
607A-608A). Also reported are protamine fragments (U.S. Pat. No.
6,624,141) and small synthetic peptides (U.S. Pat. No. 6,200,955)
as heparin or low molecular weight heparin antidotes; and thrombin
muteins (U.S. Pat. No. 6,060,300) as antidotes for thrombin
inhibitors. Prothrombin intermediates and derivatives have been
reported as antidotes to hirudin and other thrombin inhibitors
(U.S. Pat. Nos. 5,817,309 and 6,086,871). Despite the absence of
solid clinical data, dabigatran-associated severe bleeding is
preferably treated with the non-specific reversal agent activated
prothrombin complex concentrate (APCC) (Siegal et al., Blood 2014,
123:1152-1158).
[0005] Newly developed direct factor Xa (FXa) inhibitors (DFXIs),
such as rivaroxaban, apixaban and edoxaban, are anticoagulants and
may largely replace the classic VKAs in the near future because of
their rapid therapeutic effectiveness, ease of dosing and lack of
monitoring requirements due to fewer drug and food interactions and
predictable pharmacokinetics. DFXIs are small compound inhibitors
that have been specifically designed to tightly bind to and halt
the activity of blood coagulation FXa. Coagulation FXa is an
essential serine protease that normally circulates as an .about.60
kDa inactive precursor (zymogen) coagulation factor X (FX) in
blood, but is converted upon vascular damage to its active protease
form in a complex series of protein activation steps, collectively
known as the blood coagulation cascade. Central to this system is
the formation of the cofactor-protease complex known as the
prothrombinase complex that consists of coagulation FXa in
association with the cofactor factor Va (FVa), which assemble
exclusively on a negatively charged phospholipid membrane and
convert inactive prothrombin into the active serine protease
thrombin.
[0006] A major drawback to the use of the DFXIs is the absence of a
specific and adequate reversal strategy to prevent and stop
potential life-threatening bleeding complications associated with
its anticoagulant therapy.
[0007] Since DFXIs inhibit both free and prothrombinase-bound
coagulation FXa (European Medicines Agency, 2008, CHMP assessment
report for Xarelto, Procedure No. EMEA/H/C/000944, Doc.Ref.:
EMEA/543519/2008), effective restoration of normal hemostasis
would, therefore, require either full replacement of circulating
coagulation FXa or effective removal of inhibitory compounds from
blood.
[0008] Currently, there are no specific reversal strategies
available to prevent and stop potential life-threatening bleeding
complications associated with DFXI therapy. Next to life-supporting
and surgical therapies, non-specific reversal therapy using 3- and
4-factor PCC may be considered based on limited evidence (Siegal et
al., Blood 2014, 123:1152-1158; Levi et al., J. Thrombosis
Haemostatis 2014, Published online 8 May 2014; doi:
10.1111/jth.12599). A reversal strategy specific for
DFXI-associated bleeding is in development, which is based on a
catalytically inactive form of recombinant FXa (andexanet alpha)
that serves as a decoy for DFXIs by binding and thereby trapping
circulating DFXIs, thereby enabling endogenous coagulation FXa to
normally participate in coagulation (Lu et al., Nature Medicine
2013, 19:446). A downside to this approach is that high doses of
andexanet alpha need to be administered since stoichiometric
concentrations are required to attain inhibition (400 mg IV bolus
in phase III trial; Portola News Release Mar. 19, 2014).
Furthermore, since the half life of DFXI partially depends on renal
clearance, the amount of decoy FXa required to trap all circulating
inhibitory molecules may even be higher in the case of renal
failure. This reversal strategy does not provide a fast and direct
procoagulant response, as the response is dependent on the
generation of free, endogenous coagulation FXa.
[0009] At this moment, a direct, adequate reversal strategy to
prevent and stop potential life-threatening bleeding complications
associated with DFXI anticoagulant therapy is not available.
BRIEF SUMMARY
[0010] This disclosure solves this problem by providing, as an
adequate reversal strategy to prevent and stop potential
life-threatening bleeding complications associated with DFXI
anticoagulant therapy, a recombinant protein comprising, or
consisting of, a mammalian, preferably primate, more preferably
human, coagulation FXa polypeptide, the polypeptide having an
alteration in a region of amino acid residues corresponding to the
region of amino acid residues between Gly-289 and Asp-320 of SEQ ID
NO:1, preferably between Glu-297 and Asp-320 of SEQ ID NO:1, more
preferably between Val-305 and Asp 320 of SEQ ID NO:1 and most
preferably between His-311 and Asp-320 or between His-311 and
Tyr-319 of SEQ ID NO:1, wherein the alteration is an insertion
and/or replacement and/or deletion of at least one amino acid
residue, preferably an insertion of at least one amino acid
residue. For clarification purposes, the amino acid residue
numbering is based on the human coagulation FX amino acid sequence
as provided in SEQ ID NO:1.
[0011] It was found that a catalytically active human coagulation
FXa, with an altered amino acid composition at a region between the
Gly and Asp corresponding to Gly 289 and Asp-320 of SEQ ID NO:1,
participates in the coagulation cascade as a procoagulant, whereby
the factor has a decreased sensitivity to inhibition by DFXIs,
compared to a coagulation FXa not having the altered amino acid
composition. This disclosure provides, therefore, a procoagulant
antidote that does not depend on the generation of free, endogenous
coagulation FXa and offers a fast and direct reversal strategy to
prevent and stop complications associated with DFXI anticoagulant
therapy.
[0012] The amino acid sequence of human coagulation FX is provided
in SEQ ID NO:1 and can be found in GENBANK.RTM. under "AAH46125.1."
The amino acid residue numbering in this sequence is based on the
human coagulation FX sequence. Coagulation FX with the sequence
listed in SEQ ID NO:1 is a precursor containing a prepro-leader
sequence (amino acid residues 1 to 40 of SEQ ID NO:1), followed by
sequences corresponding to a coagulation FX light chain (amino acid
residues 41 to 179 of SEQ ID NO:1), a RKR triplet (amino acid
residues 180 to 182 of SEQ ID NO:1) which is removed during
secretion of coagulation FX, and a coagulation FX heavy chain
(amino acid residues 183 to 488 of SEQ ID NO:1) containing the
activation peptide (AP) (amino acid residues 183 to 234 of SEQ ID
NO:1) and the catalytic serine protease domain (amino acid residues
235 to 488 of SEQ ID NO:1).
[0013] Maturation of human coagulation FX involves inter alia
proteolytic cleavage and post-translational modification in the
Golgi apparatus. The mature FX protein is a two-chain molecule,
composed of a light chain and a heavy chain that are linked by a
disulfide bond (Uprichard et al., Blood Reviews 2002, 16:97-110).
Mature human coagulation FX is activated by cleavage of a peptide
bond on the heavy chain between Arg 234 and Ile-235 of SEQ ID NO:1,
thereby releasing a 52-residue activation peptide from the heavy
chain of coagulation FX. The resulting disulfide-linked light chain
and truncated heavy chain constitute an activated FXa
polypeptide.
[0014] The amino acid sequence of the light chain of human
coagulation FXa is provided in SEQ ID NO:2. The amino acid sequence
of the heavy chain of human coagulation FXa is provided in SEQ ID
NO:3.
[0015] The term "recombinant," as used herein, refers to a protein
that is produced using recombinant DNA techniques known to the
person skilled in the art. A recombinant coagulation FX or FXa
polypeptide is also indicated as rFX or rFXa. A recombinant protein
preferably is not identical to a native protein, for example,
because the amino acid composition differs and/or because of a
difference in post-translational modification such as
glycosylation.
[0016] The term "alteration," as used herein, refers to an
insertion and/or replacement and/or deletion of at least one amino
acid residue. The alteration preferably is an insertion of at least
one amino acid.
[0017] The phrase "recombinant protein comprising a coagulation FXa
polypeptide," as used herein, is meant to encompass a protein that
comprises a recombinant coagulation FXa polypeptide, preferably
mammalian, more preferably primate, and most preferably of human
origin. The phrase includes, for example, a recombinant mammalian
precursor protein, such as human coagulation FX, that is processed
and/or activated into a mammalian coagulation rFXa polypeptide.
Thus, a protein of the disclosure is preferably a recombinant
mammalian, preferably primate, more preferably human coagulation
FX, having an insertion and/or replacement and/or deletion,
preferably an insertion, of at least one amino acid residue in a
region of amino acid residues corresponding to the region of amino
acid residues between Gly-289 and Asp-320 of SEQ ID NO:1,
preferably between Glu-297 and Asp-320 of SEQ ID NO:1, more
preferably between Val-305 and Asp-320 of SEQ ID NO:1 and most
preferably between His-311 and Asp-320 of SEQ ID NO:1. In addition,
the phrase includes a protein that comprises one or more additional
amino acid sequences, besides the coagulation rFXa polypeptide, for
example, an amino acid sequence that constitutes a tag, for
example, a FLAG tag as described in EP0150126, and/or one or more
other identification peptides.
[0018] In one embodiment, therefore, a recombinant protein
comprising a coagulation FXa polypeptide according to the
disclosure is a coagulation factor X polypeptide, the polypeptide
having an alteration in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-289
and Asp-320, preferably between His-311 and Asp-320 of SEQ ID NO:1;
wherein the alteration is an insertion of at least one amino acid
residue.
[0019] The term "coagulation FX," as used herein, refers to an
inactive coagulation FX precursor protein. The skilled person knows
that coagulation FX is also referred to as preproprotein FX. As is
used herein, a coagulation FX comprises a coagulation FXa
polypeptide.
[0020] The term "mature coagulation FX," as used herein, refers to
an inactive coagulation FX protein that is composed of a light
chain and a heavy chain that are linked by a disulfide bond. This
FX protein is also referred to as proprotein FX, or zymogen FX. As
is used herein, a mature coagulation FX comprises a coagulation FXa
polypeptide.
[0021] A protein of the disclosure preferably comprises, or is, a
mammalian, preferably primate, more preferably human or humanized,
coagulation FXa polypeptide, having an insertion and/or replacement
and/or deletion, preferably an insertion, of at least one amino
acid residue in a region of amino acid residues corresponding to
the region of amino acid residues between Gly-289 and Asp-320 of
SEQ ID NO:1.
[0022] The term "humanized," as is used herein, refers to the
replacement or humanization of preferably exterior amino acid
residues of a protein of one species for amino acid residues that
are present in a human homologue of the protein so that the
proteins of the first species will not be immunogenic, or are less
immunogenic, when applied to a human. The replacement of exterior
residues preferably has little, or no, effect on the interior
domains, or on the interdomain contacts between light and heavy
chains. A protein of the disclosure of non-human origin, preferably
mammalian origin, more preferably primate origin, is preferably
humanized in order to reduce the immunogenicity of the protein in a
human.
[0023] A non-human protein of the disclosure preferably comprises a
humanized mammalian, more preferably a humanized primate,
coagulation FXa polypeptide, as the risk of an antigenic response
upon administration in the human body is expected to be lower as
compared to a protein of the disclosure comprising a non-humanized
coagulation FXa polypeptide.
[0024] In the context of humanizing proteins, attention can be paid
to the process of humanizing that is applicable to antibodies. This
process makes use of the available sequence data for human antibody
variable domains compiled by Kabat et al., "Sequences of Proteins
of Immunological Interest," 4th ed. (1987), Bethesda, Md., National
Institutes of Health, updates to this database, and other
accessible U.S. and foreign databases (both nucleic acid and
protein). Non-limiting examples of the methods used to generate
humanized antibodies include EP 519596; U.S. Pat. No. 6,797,492;
and described in Padlan et al., Mol. Immunol. 1991, 28:489-498.
Further exemplifying the process of humanization of non-human
proteins, Sarkar et al., "Journal of Lipids" 2012, Article ID
610937, p. 1-13, described that Paraoxonase-1 was successfully
humanized by altering the surface of the enzyme to reflect the
human sequence.
[0025] The term "coagulation FXa polypeptide" refers to the
catalytically active form of a coagulation FX. The coagulation FXa
polypeptide is obtained by cleavage of the activation peptide from
the heavy chain of a mature coagulation FX. A coagulation FXa
polypeptide activates prothrombin and, as a result, promotes
coagulation. In the context of the disclosure, a protein is a
coagulation FXa polypeptide if it is a procoagulant serine protease
and if the full-length amino acid sequence of the protein comprises
stretches of, or single, amino acid residues that correspond to
stretches of, or single, amino acid residues that are conserved
between coagulation FX factors of different species, as is
indicated in FIGS. 8A-8C. For example, a procoagulant serine
protease comprising a polypeptide that contains stretches of amino
acid residues that correspond to amino acid residues Cys-246 to
Ala-250, Phe-260 to Leu-266 and/or Asp-413 to His-423 of SEQ ID
NO:1, is assumed to be a coagulation FXa polypeptide. The
coagulation FXa polypeptide is preferably obtained by local and/or
topical application of a recombinant protein according to the
disclosure. Methods to determine whether a protein is a serine
protease are known in the art and include sequence comparison and
use of a protease detection kit, for example, from
Sigma-Aldrich.
[0026] The term "mammalian coagulation FXa polypeptide," as used
herein, refers to a coagulation FXa polypeptide that is
endogenously present in a mammal, preferably a primate, more
preferably a human.
[0027] The term "coagulation inhibitor," as used herein, refers to
an anti-coagulation agent. The term "coagulation inhibitor"
includes, but is not limited to: (i) agents, such as heparin, that
stimulate the activity of antithrombin, (ii) coumarin-based oral
anticoagulant vitamin K antagonists, such as warfarin,
acenocoumarol and phenprocoumon, and (iii) DFXIs.
[0028] The term "DFXI," as used herein, refers to direct FXa
inhibitors, for example, oral direct FXa inhibitors. DFXIs are
small compound inhibitors that bind to and halt the activity of
coagulation FXa. The group of DFXIs includes, but is not limited
to, rivaroxaban (5-chloro-N-[[(5
S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-5-oxazolidinyl]methyl]-2-thiop-
henecarboxamide), apixaban
(1-(4methoxyphenyl)-7-oxo-6-[4-(2-oxopiperidin-1-yl)phenyl]-4,5,6,7-tetra-
hydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide), edoxaban
(N'-(5-chloropyridin-2-yl)-N-[(1S,2R,4S)-4-(dimethylcarbamoyl)-2-[(5-meth-
yl-6,7-dihydro-4H-[1,3]thiazolo[5,4-c]pyridine-2-carbonyl)amino]cyclohexyl-
]oxamide; 4-methylbenzenesulfonic acid), betrixaban
(N-(5-chloropyridin-2-yl)-2-[[4-(N,N-dimethylcarbamimidoyl)benzoyl]amino]-
-5-methoxybenzamide), darexaban
(N-[2-[[4-(Hexahydro-4-methyl-1H-1,4-diazepin-1-yl)benzoyl]amino]-3-hydro-
xyphenyl]-4-methoxybenzamide), otamixaban (methyl
(2R,3R)-2-[(3-carbamimidoylphenyl)methyl]-3-[[4-(1-oxidopyridin-1-ium-4-y-
l)benzoyl]amino]butanoate), eribaxaban
(2R,4R)-1-N-(4-chlorophenyl)-2-N-[2-fluoro-4-(2-oxopyridin-1-yl)phenyl]-4-
-methoxypyrrolidine-1,2-dicarboxamide), letaxaban
(1-[1-[(2S)-3-(6-chloronaphthalen-2-yl)sulfonyl-2-hydroxypropanoyl]piperi-
din-4-yl]-1,3-diazinan-2-one, LY517717
(N-[2-[4-(1-methylpiperidin-4-yl)piperazin-1-yl]-2-oxo-1-phenylethyl]-1H--
indole-6-carboxamide) and 813893
(N-cyclohexyl-N-[2-[(4-methyl-1,3-thiazol-2-yl)amino]-2-oxoethyl]furan-2--
carboxamide). The terms "DOAC" (direct oral anticoagulant) and
"DFXI" are used interchangeably herein.
[0029] The term "homologous," as used herein, refers to amino acid
sequence identity between two amino acid sequences, expressed as a
percentage of the total length of the two amino acid sequences.
Sequence identity is determined by comparing the identity of
individual amino acid residues of an amino acid sequence to the
corresponding amino acid residue in another amino acid
sequence.
[0030] The term "region," as used herein, refers to a stretch of
amino acid residues that is bordered by two amino acid residues.
The numbering of amino acid residues as applied herein is based on
the amino acid sequence of SEQ ID NO:1.
[0031] The term "insertion" or "inserted," as used herein, refers
to the addition of amino acid residues in a specific region of a
native coagulation FXa polypeptide, thereby increasing the number
of amino acid residues in the region, compared to the number of
amino acid residues in that region of the native coagulation factor
FXa polypeptide.
[0032] The term "replacement" or "replaced," as used herein, refers
to the substitution of one or more amino acid residues in a
specific region, or at a specific site, of a coagulation factor Xa
polypeptide, thereby altering the amino acid sequence, but not the
number of amino acid residues in the region. A replacement is the
consequence of the deletion of an amino acid residue followed by
the insertion of a different amino acid residue at the same
position.
[0033] The term "deletion" or "deleted," as used herein, refers to
deleting one or more amino acid residues in a specific region, or
at a specific site, of a coagulation factor Xa polypeptide, thereby
reducing the number of amino acid residues in the region of the
polypeptide.
[0034] The term "native coagulation FXa polypeptide," as used
herein, refers to an endogenous coagulation FXa polypeptide that
naturally occurs in an animal, preferably in a mammal, more
preferably in a primate, more preferably in a human.
[0035] The term "amino acid composition," as used herein, refers to
the amino acid sequence and length of a stretch of amino acid
residues, wherein the length is determined by the number of amino
acid residues in that stretch.
[0036] The insertion, replacement and/or deletion, preferably
insertion, of one or more amino acid residues can be performed
using recombinant DNA techniques that are well known to the person
skilled in the art. For example, the person skilled in the art can
use synthetic DNA, PCR technology and molecular cloning to obtain
recombinant DNA constructs having a DNA sequence encoding a protein
of this disclosure. Suitable methods and means are described in
Green and Sambrook, Molecular Cloning: A Laboratory Manual, CSHL
Press, 2012.
[0037] The phrase "corresponding to the region of amino acid
residues between," for example, with regard to the region of amino
acid residues corresponding to the region of amino acid residues
between His-311 and Asp-320 of SEQ ID NO:1," is used herein to
indicate that the residue number of the conserved His and Asp
residues of another coagulation FXa corresponding to the His-311
and Asp-320 of SEQ ID NO:1, may differ from the residue number
attributed to the His and Asp residue in SEQ ID NO:1 (see FIGS.
8A-8C). Differences in amino acid residue numbers can, for example,
be the result of a different way of numbering amino acid residues.
Also, a difference in amino acid residue number can be the result
of a difference in length of a coagulation FXa polypeptide as
compared to the length of the human coagulation FXa polypeptide
that is indicated in FIGS. 8A-8C. Similarly, the amino acid
residues Gly-289, Glu-297, Val-305 and Tyr-319, of SEQ ID NO:1, are
conserved between coagulation FXa polypeptides of different species
(see FIGS. 1 and 8A-8C). It is, therefore, possible to identify
amino acid residues that correspond to the amino acid residues in
another coagulation FXa polypeptide. The person skilled in the art
will, therefore, understand that the amino acid residue numbering
as applied herein is not limiting for the disclosure, but is only
applied for clarity purposes.
[0038] The skilled person will know how to identify a region of
amino acid residues that corresponds to the region of amino acid
residues between the conserved amino acid residues of SEQ ID NO:1
that border a region as described herein. When the amino acid
residues 289-322 of SEQ ID NO:1 are aligned with the corresponding
amino acid residues in coagulation FXa polypeptides of different
species, it is to be concluded that the amino acid residues at
positions 289, 297, 305, 311, 313, 314, 318, 319, 320, and 322 of
SEQ ID NO:1 are conserved, though not identical, in coagulation FXa
polypeptides of different species, especially in mammals, wherein
Asp-322 of SEQ ID NO:1 is a highly conserved catalytic residue
(Asp-102 in chymotrypsinogen numbering; Bode et al., EMBO Journal
1989, 8:3467-3475; Messier et al., Blood Coagulation and
Fibrinolysis 1996, 7:5-14 and FIGS. 1, 8A, 8B and 8C).
[0039] Due to the highly conserved nature of the region of amino
acid residues in and around Gly-289 and Asp-320 of SEQ ID NO:1, or
in and around the corresponding Gly and Asp residues in a non-human
coagulation FXa, the person skilled in the art is able to identify
a region of amino acid residues corresponding to the region of
amino acid residues between Gly-289 and Asp-320 of SEQ ID NO:1. The
same general principle applies to other amino acid residues that
border a region as described herein. In other words, the conserved
nature of specific amino acid residues will give the skilled person
an unambiguous pointer as to which amino acid residues constitute a
region.
[0040] A person skilled in the art will understand that this
disclosure relates to the amino acid composition of a region of
amino acid residues corresponding to the region of amino acid
residues between Gly-289 and Asp-320, most preferably between
His-311 and Asp-320 of SEQ ID NO:1. Therefore, the person skilled
in the art will understand that the amino acid sequence of the
remainder of a protein of the disclosure can vary, under the
condition that the protein remains a, or is activated into a,
procoagulant FXa polypeptide with decreased sensitivity to DFXIs.
The remainder of a protein of the disclosure may thus vary as it,
for example, varies between coagulation FX, or coagulation FXa,
polypeptides of different species.
[0041] The number of amino acid residues in a region corresponding
to the region between Gly-289 and Asp-320, preferably between
His-311 and Asp-320 of SEQ ID NO:1 is conserved between coagulation
FX proteins of different species, especially between species
belonging to the group of mammals or to the group of primates. This
region is also present in zymogen FX protein and FXa polypeptide.
Hence, the number of amino acid residues is also conserved in
zymogen FX protein and FXa polypeptide and in the corresponding
region of zymogen FX protein and FXa polypeptide. The conserved
number of amino acid residues in a region of amino acid residues
corresponding to the region between Gly-289 and Asp-320 of SEQ ID
NO:1 is thirty, not including Gly-289 and Asp-320. The conserved
number of amino acid residues in a region of amino acid residues
corresponding to the region between His-311 and Asp-320 of SEQ ID
NO:1 is eight, not including His-311 and Asp-320.
[0042] It was found that the insertion and/or replacement and/or
deletion, preferably the insertion, of at least one amino acid
residue in a region of amino acid residues corresponding to the
region of amino acid residues between Gly-289 and Asp-320,
preferably between His-311 and Asp-320 of SEQ ID NO:1 in a protein
of the disclosure, yields a catalytically active coagulation FXa
with decreased sensitivity to inhibition by DFXIs.
[0043] Tyr-319 of human FXa has been demonstrated to be a
DFXI-coordinating residue (Roehrig et al., J. Med. Chem. 2005,
48:5900-5908; Pinto et al., J. Med. Chem. 2007, 50:5339-5356),
while Asp-322 of SEQ ID NO:1 is present in the catalytic serine
protease site (Messier et al., Blood Coagulation and Fibrinolysis
1996, 7:5-14). Without being bound by theory, it is possible that
the close proximity of an altered amino acid residue, such as an
insertion of at least one amino acid residue, in the region between
Gly-289 and Asp-320 to the DFXI-coordinating residue Tyr-319 of SEQ
ID NO:1, or the corresponding tyrosine, and/or the close proximity
to the catalytic domain is responsible for the decreased
sensitivity for a DFXI. It is found that the region of amino acid
residues corresponding to the region of amino acid residues between
Gly-289 and Asp-320 of SEQ ID NO:1 in a protein of the disclosure
can be altered in amino acid residue number and in amino acid
sequence, thereby generating a catalytically active coagulation FXa
with decreased sensitivity for DFXIs.
[0044] The alteration is selected from an insertion, a replacement
and/or a deletion, and preferably is an insertion, more preferably
an insertion combined with an alteration of at least one amino acid
in the region between Gly-289 and Asp-320 of SEQ ID NO:1.
[0045] Particularly preferred is a protein of the disclosure
wherein the insertion is 1-50, preferably 1-20, amino acid
residues. The insertion in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-289
and Asp-320, preferably between His-311 and Asp-320, of SEQ ID NO:1
in a protein of the disclosure comprises or consists of between
1-50, preferably between 1-20, amino acid residues. The insertion
preferably comprises, or consists of, at least 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acid
residues, resulting in a total of 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, or 20, 21, 22, 23, 24, 25, 26, 27, or 28, respectively,
amino acids between His-311 and Asp-320. Particularly preferred is
the insertion of at least five amino acid residues, such as an
insertion of 9, 12 or 13 amino acid residues. The person skilled in
the art will understand that the amino acid residues can be
inserted at any position in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-289
and Asp-320 of SEQ ID NO:1. An amino acid residue suitable for
insertion is selected from the group of twenty amino acid residues
as listed in Table 1. The person skilled in the art will understand
that the inserted amino acid residues may undergo a
post-translational chemical alteration in vivo or in vitro. As is
indicated herein above, the person skilled in the art can use
synthetic DNA, PCR technology and molecular cloning to obtain
recombinant DNA constructs having a DNA sequence encoding a protein
of this disclosure having an insertion of between 1-50 amino acid
residues in the region of amino acid residues corresponding to the
region between Gly-289 and Asp-320 of SEQ ID NO:1.
[0046] The insertion in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-289
and Asp-320 of SEQ ID NO:1 in a protein of the disclosure is
preferably between Thr-315 and Lys-316, between Lys-316 and
Glu-317, between Glu-317 and Thr-318, and/or between Thr-318 and
Tyr-319 of SEQ ID NO:1 or between two amino acid residues
corresponding to these amino acid residues in a non-human
coagulation FXa polypeptide.
[0047] Particularly preferred is a protein of the disclosure
wherein the replacement is 1-30, preferably 1-8, more preferably 6
or 7, amino acid residues. The replacement of amino acid residues
in a region of amino acid residues corresponding to the region of
amino acid residues between Gly-289 and Asp-320 of SEQ ID NO:1 in a
protein of the disclosure preferably comprises, or consists of,
between 1-30 amino acid residues in a region corresponding to the
region of amino acid residues between Gly-289 and Asp-320 of SEQ ID
NO:1. The replacement preferably comprises, or consists of, 1, 2,
3, 4, 5, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 26, 27, 28, 29 or 30 amino acid residues. It is
preferred that conserved amino acid residues such as, for example,
Glu-297, Val-305 and/or His-311 as indicated in SEQ ID NO:1 are not
replaced. Particularly preferred is the replacement of either six
or seven amino acid residues.
[0048] An amino acid residue present in a region corresponding to
the region of amino acid residues between Gly-289 and Asp-320 of
SEQ ID NO:1 of a protein of the disclosure is preferably replaced
by any one of the amino acid residues listed in Table 1, preferably
by an amino acid of the same group as is indicated in the columns
"side chain polarity" and "side chain charge" in Table 1.
Preferably, one or more of Asn-312, Arg-313, Phe-314, Thr-315,
Lys-316, Glu-317, Thr-318 and Tyr-319 of SEQ ID NO:1, or their
corresponding amino acid residues in a non-human protein of the
disclosure, are replaced by any one of the amino acid residues as
indicated in Table 1. Asn-312 of SEQ ID NO:1 is preferably replaced
by a Thr or Lys residue. Arg-313 is preferably replaced by an amino
acid residue with a basic polarity and positively charged
side-chain (see Table 1), more preferably by a Lys residue. Amino
acid residue Thr-315 is preferably replaced by a polar amino acid
residue with a neutral side-chain or by a nonpolar amino acid
residue with a neutral side-chain, more preferably by a Val
residue. Lys-316 of SEQ ID NO:1 is preferably replaced by a Pro
residue. Glu-317 of SEQ ID NO:1 is preferably replaced by a Val
residue. Thr-318 is preferably replaced by a polar amino acid
residue with a neutral side-chain or by a nonpolar amino acid
residue with a neutral side-chain, more preferably by a Ser or Ala
residue.
[0049] The replacement of amino acid residues in a region of amino
acid residues corresponding to the region of amino acid residues
between Gly-289 and Asp-320 of SEQ ID NO:1 in a protein of the
disclosure preferably comprises, or consists of, at least two amino
acid residues. Any combination of at least two amino acid residues
is envisaged in the disclosure, for example, a replacement of
Asn-312 of SEQ ID NO:1 and Lys-316 of SEQ ID NO:1 by a Pro residue
and an Ala residue, respectively, or replacement of Asn-312,
Arg-313, Thr-315, Lys-316, Glu-317, Thr-318 and Tyr-319 of SEQ ID
NO:1 by any one of the amino acid residues listed in Table 1.
Particularly preferred is a protein of the disclosure having a
replacement of (i) Asn-312, (ii) Arg-313, (iii) Thr-315, (iv)
Lys-316, (v) Glu-317 and (vi) Thr-318 of SEQ ID NO:1 by a (i) Thr
or Pro residue, (ii) Lys residue, (iii) Val residue, (iv) Pro
residue, (v) Val residue and (vi) Ser or Ala residue,
respectively.
[0050] The person skilled in the art will understand that when
amino acid residues are replaced in a region of amino acid residues
corresponding to the region between Gly-289 and Asp-320 of SEQ ID
NO:1 of a non-human protein of the disclosure, only those amino
acid residues are replaced that are not already present in a
preferred protein of the disclosure. The person skilled in the art
will know that the aforementioned reference to SEQ ID NO:1 is only
made in the context of exemplifying the replacement of amino acid
residues in a specified region of amino acid residues. Therefore,
the skilled person will have an indication which one or more amino
acid residues they may replace in a non-human coagulation FXa for
what other amino acid residue or residues.
[0051] A protein of the disclosure may further comprise a deletion
of at least one amino acid residue in a region of amino acid
residues corresponding to the region of amino acid residues between
Gly-289 and Asp-320 of SEQ ID NO: 1. Particularly preferred is a
protein of the disclosure having a deletion of at least 1, 2, 3, 4,
5, 6, 7, 8, 10, 15, 20 or 30 amino acid residues.
[0052] A preferred protein of the disclosure comprises a
combination of an insertion and a replacement, or a combination of
an insertion, a replacement, and/or a deletion. Insertions and
deletions may occur independently of each other and it is thus
possible that, for example, an insertion of five amino acid
residues and a deletion of five amino acids are present at
different amino acid positions in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-289
and Asp-320 of SEQ ID NO:1, without affecting the total number of
amino acid residues in a coagulation FX. The skilled person will
understand that an insertion or deletion changes the amino acid
residue numbering in a protein. With regard to a convenient
assessment of where an alteration is located and what the
alteration constitutes, the skilled person can perform a multiple
alignment of the amino acid sequence of different coagulation FX
proteins as shown in FIGS. 8A-8C. The skilled person can deduce
from such an alignment which amino acid residues are altered. The
skilled person can use conserved amino acid residues, for example,
Glu-297, Val-305 and/or His-311 as markers to assess the amino acid
residue number where the alteration took place.
[0053] Particularly preferred is a protein of the disclosure
wherein the insertion is 1-50, preferably 1-20, amino acid residues
and wherein the replacement is 1-7, preferably 6, amino acid
residues. The preferred protein has an insertion of between 1-50,
preferably between 1-20, amino acid residues, combined with a
replacement of between 1-8, preferably either 6 or 7, amino acid
residues in a region of amino acid residues corresponding to the
region of amino acid residues between Gly-289 and Asp-320 of SEQ ID
NO:1.
[0054] A more preferred protein of the disclosure has an insertion
of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, or 20 amino acid residues and a replacement of at least
1, 2, 3, 4, 5, 6 or 7 amino acid residues in a region of amino acid
residues corresponding to the region of amino acid residues between
Gly-289 and Asp-320 of SEQ ID NO:1, meaning that the insertion of
at least 1-20 amino acid residues is combined with a replacement of
at least 1, 2, 3, 4, 5, 6 or 7 amino acid residues. The disclosure
is directed to all possible combinations of the aforementioned
insertion and replacement. Particularly preferred is a protein
having an insertion of 12 or 13 amino acid residues and a
replacement of 6 amino acid residues in a region of amino acid
residues corresponding to the region of amino acid residues between
Gly-289 and Asp-320 of SEQ ID NO:1.
[0055] A protein of the disclosure most preferably comprises a
region of amino acid residues having the amino acid sequence of SEQ
ID NO:4, SEQ ID NO:5, SEQ ID NO:9, SEQ ID NO:10 or SEQ ID NO:11
between amino acid residues corresponding to the amino acid
residues His-311 and Asp-320 of SEQ ID NO:1.
[0056] Furthermore, alteration of Arg-366, Glu-369, Phe-396,
Asp-413, Ala-414, Cys-415, Gln-416, Ser-419, Val-437, Ser-438,
Trp-439, Gly-440, Glu-441, Gly-442, Cys-443, Gly-450, Ile-451 and
Tyr-452 of SEQ ID NO:1 is likely to result in a protein that is
desensitized to DFXIs. Without being bound by theory, Arg-366,
Glu-369, Phe-396, Asp-413, Ala-414, Cys-415, Gln-416, Ser-419,
Val-437, Ser-438, Trp-439, Gly-440, Glu-441, Gly-442, Cys-443,
Gly-450, Ile-451 and Tyr-452 of SEQ ID NO:1 are likely to be
DFXI-coordinating residues. Literature indirectly supports this
view, as it is shown that at least some of these residues are
involved in binding of DFXIs (Roehrig et al., J. Med. Chem. 2005,
48:5900-5908; Pinto et al., J. Med. Chem. 2007, 50:5339-5356). A
protein of the disclosure preferably has replaced or deleted an
amino acid residue corresponding to Arg-366, Glu-369, Phe-396,
Asp-413, Ala-414, Cys-415, Gln-416, Ser-419, Val-437, Ser-438,
Trp-439, Gly-440, Glu-441, Gly-442, Cys-443, Gly-450, Ile-451 or
Tyr-452 of SEQ ID NO:1. Amino acid residues Arg-366, Glu-369,
Phe-396, Asp-413, Ala-414, Cys-415, Gln-416, Ser-419, Val-437,
Ser-438, Trp-439, Gly-440, Glu-441, Gly-442, Cys-443, Gly-450,
Ile-451 and/or Tyr-452 of SEQ ID NO:1, or the corresponding amino
acid residues in a related protein, are preferably replaced by any
one of the amino acid residues as listed in Table 1. Also, a
protein of the disclosure preferably has an insertion of at least
one amino acid residue, such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20 amino acid residues in a region
of amino acid residues corresponding to the region between the 15
amino acid residues located at the N-terminal and 15 amino acid
residues located at the C-terminal from Arg-366, Glu-369, Phe-396,
Asp-413, Ala-414, Cys-415, Gln-416, Ser-419, Val-437, Ser-438,
Trp-439, Gly-440, Glu-441, Gly-442, Cys-443, Gly-450, Ile-451
and/or Tyr-452. The alteration of Phe-396, Arg-366, Glu-369,
Asp-413, Ala-414, Cys-415, Gln-416, Ser-419, Val-437, Ser-438,
Trp-439, Gly-440, Glu-441, Gly-442, Cys-443, Gly-450, Ile-451
and/or Tyr-452 of SEQ ID NO:1. The insertion in a region as
indicated in this paragraph is preferably combined with an
alteration in the region between Gly-289 and Asp-320 of SEQ ID NO:1
as defined hereinabove.
[0057] This disclosure also encompasses proteins that are
substantially homologous and biologically equivalent to a protein
of the disclosure. A protein of the disclosure preferably has an
amino acid sequence that is more than 60%, preferably more than
70%, more preferably more than 80%, and most preferably more than
90% homologous to SEQ ID NO:1 or to the activated form thereof,
wherein the protein is catalytically active (procoagulant), or
catalytically active after processing/activation, and has a
decreased sensitivity to DFXIs, preferably a DFXI selected from the
group consisting of rivaroxaban, apixaban, edoxaban and betrixaban.
The person skilled in the art knows how the preproprotein or
proprotein of coagulation FX is processed to its catalytically
active form. The UniProt database provides an overview, under
Accession Number P00742, of the processing of human coagulation FX
to activated human coagulation FXa. The skilled person will thus be
able to determine which amino acid residues are present or absent
in coagulation FXa.
[0058] The term "decreased sensitivity to DFXIs," as used in the
context of this disclosure, refers to the concentration of a DFXI
that is required to produce 50% of the maximum inhibition (Ki),
that is higher for a polypeptide of this disclosure than for a
native coagulation FXa, wherein the native coagulation FXa is
preferably derived from blood plasma or is recombinantly produced.
The Ki of a DFXI is preferably determined by pre-incubating a
protein of the disclosure with 0.001 to 100 .mu.M of a DFXI and
subsequently performing an experiment wherein the catalytic
activity toward Spectrozyme Xa (Sekisui Diagnostics; Stamford,
Conn., USA) by peptidyl substrate conversion is assayed. The Ki of
a protein of the disclosure is preferably increased more than two
times, more preferably, increased between 50 and 100 times, and
most preferably, increased more than 100 times as compared to the
Ki of the native coagulation FXa without an alteration of at least
one amino acid residue in a region of amino acid residues
corresponding to the region of amino acid residues between Gly-298
and Asp-320 of SEQ ID NO:1.
[0059] It was unexpectedly found that a protein of the disclosure
has an increased binding affinity for coagulation FVa, the binding
partner of coagulation FXa in the prothrombinase complex, as
compared to the binding affinity of native coagulation FXa for
coagulation FVa. The binding affinity of a human or humanized
protein of the disclosure for FVa is at least two times higher than
the binding affinity of native human FXa for FVa.
[0060] Assays for determining the binding affinity are known in the
art, for example, by using a binding partner (such as FVa or FXa)
with a radiolabel. The amount of radiation emitted upon binding can
be used to calculate the binding affinity. Also, non-radioactive
methods such as surface plasmon resonance and dual polarization
interferometry can be used to quantify the binding affinity from
concentration-based assays but also from the kinetics of
association and dissociation and, in the latter, the conformational
change induced upon binding. Recently, Microscale Thermophoresis
(MST), an immobilization-free method was developed, that allows the
determination of the binding affinity between two proteins (Wienken
et al., Nature Communications 2010, 1:100). Preferably, the binding
affinity of the coagulation FVa-FXa complex is determined via
either the kinetics of prothrombin or prothrombin derivatives
(prethrombin-1, prethrombin-2) conversion (Bos et al., Blood 2009,
114:686-692), fluorescence intensity/anisotropy measurements (Bos
et al., J. Biol. Chem. 2012, 287: 26342-51), or isothermal
titration calorimetry (ITC).
[0061] The disclosure further provides a nucleic acid molecule
comprising a DNA sequence that encodes a protein of the disclosure.
The person skilled in the art will understand how to generate a DNA
sequence that encodes an amino acid sequence of a protein of this
disclosure and how to manufacture and isolate a nucleic acid
molecule with the DNA sequence using generally known recombinant
DNA techniques. The sequence of the nucleic acid molecule is
preferably codon-optimized for expression in a host cell of the
disclosure. In this way, codons are used that are favored for
high-level expression in a specific host cell.
[0062] This disclosure also provides an expression vector
comprising a nucleic acid molecule of the disclosure.
[0063] Nucleic acid molecules are preferably inserted in an
expression vector using recombinant DNA techniques known by the
person skilled in the art. Expression vectors in the context of the
disclosure direct the expression of a protein of the disclosure in
a host cell. These expression vectors are preferably replicable in
a host cell, either as episomes or as part of the chromosomal DNA.
Further, the expression vector preferably comprises (i) a strong
promoter/enhancer, such as the CMV or SV40 promoter, (ii) an
optimal translation initiation sequence, such as a ribosomal
binding site and start codon, preferably a KOZAK consensus sequence
and (iii) a transcription termination sequence, including a poly(A)
signal when the protein is expressed in eukaryotic cells. Suitable
expression vectors include plasmids and viral vectors such as
adenoviruses, adeno-associated viruses and retroviruses. The person
skilled in the art will understand that the expression vector to be
used is dependent on the host cell that is used for expression of a
recombinant protein. An expression vector of the disclosure is
preferably suited for expression of a nucleic acid molecule of the
disclosure in a prokaryotic cell including a bacterial cell, or,
more preferred, in a eukaryotic host cell, such as a yeast cell and
a mammalian cell. Particularly preferred is mammalian expression
vector pCMV4.
[0064] As an alternative, a nucleic acid molecule of the disclosure
may be inserted in the genome of a host cell. The insertion
preferably is at a locus or within a region that ensures expression
of a nucleic acid molecule of the disclosure in the host cell.
[0065] The disclosure further provides a host cell comprising a
nucleic acid molecule of the disclosure. The disclosure preferably
provides a host cell expressing a nucleic acid molecule of the
disclosure, thereby producing a protein of the disclosure. The
protein is either produced within the host cell or, preferably,
secreted from the host cell.
[0066] Suitable host cells for use in this disclosure include
prokaryotic and eukaryotic cells, such as bacterial cells, yeast
cells, insect cells, animal cells, mammalian cells, murine cells,
rat cells, sheep cells, simian cells and human cells. Examples of
suitable eukaryotic host cells include, but are not limited to, HEK
293 cells, the hamster cell line CHO and BHK-21; the murine host
cells NIH3T3, NSO and C127; the simian host cells COS and Vero; and
the human host cells HeLa, PER.C6.RTM., U-937 and Hep G2. Suitable
cells are available from public sources such as ATCC and Life
Technologies. A number of transfection techniques are known in the
art, see, e.g., Graham et al., Virology 1973, 52:456; Green et al.,
Molecular Cloning: A Laboratory Manual 2012, CSHL Press; Davis et
al., Basic Methods in Molecular Biology 1986, Elsevier; and Chu et
al., Gene 1981, 13:197. The person skilled in the art preferably
employs techniques as described in these references to introduce
one or more exogenous nucleic acid molecules into suitable host
cells.
[0067] A particularly preferred host cell for the production of a
protein of the disclosure is a HEK 293 cell.
[0068] The disclosure further provides a pharmaceutical composition
comprising a protein of the disclosure, or a pharmaceutically
acceptable salt thereof, and a pharmaceutically acceptable carrier
or excipient. A pharmaceutical composition of the disclosure
preferably comprises one or more of diluents, fillers, salts,
buffers, stabilizers, solubilizers, and other materials known in
the art. The characteristics of the carrier will depend on the
route of administration, as is known to the skilled person. To
reduce the potential thrombotic risk of administering the serine
protease FXa, a pharmaceutical composition of the disclosure
preferably comprises a protein of the disclosure that is activated
after administering to the subject.
[0069] The term "subject" refers to the group of mammals,
preferably humans.
[0070] The term "pharmaceutical composition" refers, in the context
of the invention, to a combination of a protein of the disclosure
with a carrier, inert or active, making the composition suitable
for therapeutic use in vivo or ex vivo.
[0071] The term "pharmaceutically acceptable," as used herein,
refers to a nontoxic material that is compatible with the physical
and chemical characteristics of a protein of the disclosure and
does not interfere with the effectiveness of the biological
activity of the protein.
[0072] A pharmaceutical composition of the disclosure may be
adapted for enteral administration of the composition, wherein the
composition is absorbed through the digestive tract, e.g., oral
ingestion or rectal administration. The composition is preferably
encapsulated, for example, by liposomes, to prevent proteolytic
degradation.
[0073] A pharmaceutical composition of the disclosure preferably is
applied locally, for example, at or in a wound or to a blood
vessel, preferably an artery, that supplies the wounded region with
blood. The local administration is a topical administration, for
example, in the form of a cream, foam, gel, lotion or ointment, or
a parenteral administration, for example, by injection or infusion,
to generate a local or systemic therapeutic effect. Topical
administration of a protein of the disclosure for a local effect
reduces the risk of a potential systemic thrombotic incident.
[0074] A pharmaceutical composition of the disclosure, preferably
comprising coagulation FX or a mature coagulation FX that comprises
an altered coagulation factor Xa polypeptide, is preferably
systemically administered, preferably by parenteral administration.
Systemic administration of an inactive preproprotein or inactive
proprotein will result in the formation of an active prothrombinase
complex that consists of coagulation FXa in association with FVa on
negatively charged phospholipid membranes where it converts
inactive prothrombin into the active serine protease thrombin.
[0075] A pharmaceutical composition of the disclosure is preferably
adapted for parenteral administration, wherein the composition is
intravenously, intra-arterial, subcutaneously, and/or
intramuscularly introduced. Parenteral administration involves the
injection or infusion of a pharmaceutical composition of the
disclosure into a body tissue or body fluid, whereby preferably a
syringe, needle, or catheter is used. As an alternative,
needle-less high-pressure administration may be used as means for
parenteral administration.
[0076] For injectable compositions (e.g., intravenous
compositions), the carrier may be aqueous or oily solutions,
dispersions, emulsions and/or suspensions. Preferably, the carrier
is an aqueous solution, preferably distilled sterile water, saline,
buffered saline, or another pharmaceutically acceptable excipient
for injection.
[0077] A pharmaceutical composition of the disclosure is preferably
used in a variety of therapeutical applications. For example, the
pharmaceutical composition can be used as bypassing agent in the
treatment or amelioration of disorders wherein normal blood
coagulation is impaired, such as in hemophilia A and B, including
in hemophilia A and B inhibitor patient groups, or in factor X
deficiency.
[0078] The disclosure further provides a protein according to the
disclosure or pharmaceutical composition according to the
disclosure for use in a method of completely or partially reversing
an anti-coagulant effect of a coagulation inhibitor in a
subject.
[0079] The term "anti-coagulant effect" refers to the therapeutic
effect, such as the prevention of blood clotting, that is the
result of the action of coagulation inhibitors.
[0080] The disclosure further provides the use of a protein of the
disclosure for the manufacture of a medicament for completely or
partially reversing an anti-coagulant effect of a coagulation
inhibitor in a subject.
[0081] The coagulation inhibitor preferably is a direct FXa
inhibitor (DFXI), more preferably a direct FXa inhibitor selected
from the group formed by rivaroxaban
(5-chloro-N-[[(5S)-2-oxo-3-[4-(3-oxo-4-morpholinyl)phenyl]-5-oxazolidinyl-
]methyl]-2-thiophenecarboxamide), apixaban
(1-(4methoxyphenyl)-7-oxo-6-[4-(2-oxopiperidin-1-yl)phenyl]-4,5,6,7-tetra-
hydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide), edoxaban
(N'-(5-chloropyridin-2-yl)-N-[(1S,2R,4S)-4-(dimethylcarbamoyl)-2-[(5-meth-
yl-6,7-dihydro-4H-[1,3]thiazolo[5,4-c]pyridine-2-carbonyl)amino]cyclohexyl-
]oxamide; 4-methylbenzenesulfonic acid) and/or betrixaban
(N-(5-chloropyridin-2-yl)-2-[[4-(N,N-dimethylcarbamimidoyl)benzoyl]amino]-
-5-methoxybenzamide).
[0082] The disclosure further provides a method of completely or
partially reverting an anti-coagulant effect of a coagulation
inhibitor in a subject, the method comprising administering to the
subject a therapeutically effective amount of a protein of the
disclosure or a pharmaceutical composition of the disclosure.
Preferably, a method of the disclosure is applied for preventing or
ameliorating bleeding complications that are associated with
anticoagulant therapy.
[0083] The term "therapeutically effective amount" as used herein
means that the amount of the active ingredient contained in the
pharmaceutical composition to be administered is of sufficient
quantity to achieve the intended purpose, such as, in this case, to
completely or partially reverse an anti-coagulant effect of a
coagulation inhibitor. The amount of active ingredient, i.e., a
protein of the disclosure, in a pharmaceutical composition
according to the disclosure preferably is in the range of about 50
mg to about 600 mg. A pharmaceutical composition according to the
disclosure is preferably administered only once, twice or three
times, preferably only once, to a subject in need of complete or
partial reversal of an anti-coagulant effect of a coagulation
inhibitor.
[0084] For the purpose of clarity and a concise description,
features are described herein as part of the same or separate
embodiments; however, it will be appreciated that the scope of the
disclosure may include embodiments having combinations of all or
some of the features described.
TABLE-US-00001 (human coagulation factor X protein) SEQ ID NO: 1 1
mgrplhlvll saslagllll geslfirreq annilarvtr ansfleemkk ghlerecmee
61 tcsyeearev fedsdktnef wnkykdgdqc etspcqnqgk ckdglgeytc
tclegfegkn 121 celftrklcs ldngdcdqfc heeqnsvvcs cargytladn
gkaciptgpy pcgkqtlerr 181 krsvaqatss sgeapdsitw kpydaadldp
tenpfdlldf nqtqpergdn nltrivggqe 241 ckdgecpwqa llineenegf
cggtilsefy iltaahclyq akrfkvrvgd rnteqeegge 301 avhevevvik
hnrftketyd fdiavlrlkt pitfrmnvap aclperdwae stlmtqktgi 361
vsgfgrthek grqstrlkml evpyvdrnsc klsssfiitq nmfcagydtk qedacqgdsg
421 gphvtrfkdt yfvtgivswg egcarkgkyg iytkvtaflk widrsmktrg
lpkakshape 481 vitssplk (Light chain of human coagulation factor
Xa) SEQ ID NO: 2 1 ansfleemkk ghlerecmee tcsyeearev fedsdktnef
wnkykdgdqc etspcqnqgk 61 ckdglgeytc tclegfegkn celftrklcs
ldngdcdqfc heeqnsvvcs cargytladn 121 gkaciptgpy pcgkqtler 139
(Heavy chain of human coagulation factor Xa) SEQ ID No 3 1
ivggqeckdg ecpwqallin eenegfcggt ilsefyilta ahclyqakrf kvrvgdrnte
61 qeeggeavhe vevvikhnrf tketydfdia vlrlktpitf rmnvapaclp
erdwaestlm 121 tqktgivsgf grthekgrqs trlkmlevpy vdrnscklss
sfiitqnmfc agydtkqeda 181 cqgdsggphv trfkdtyfvt givswgegca
rkgkygiytk vtaflkwidr smktrglpka 241 kshapevits splk SEQ ID NO: 4 1
tkfvppnyyyvhqnfdrvay SEQ ID NO: 5 1 kkfvppkksqefyekfdlvsy (human
coagulation FX gene; 1-1473 bp) SEQ ID NO: 6
atggcgcacgtccgaggcttgcagctgcctggctgcctggccctggctgccctgtgtagccttgtgcacagcca-
gca
tgtgttcctggctcctcagcaagcacggtcgctgctccagcgggtccggcgagccaattcctttcttgaagaga-
tga
agaaaggacacctcgaaagagagtgcatggaagagacctgctcatacgaagaggcccgcgaggtctttgaggac-
agc
gacaagacgaatgaattctggaataaatacaaagatggcgaccagtgtgagaccagtccttgccagaaccaggg-
caa
atgtaaagacggcctcggggaatacacctgcacctgtttagaaggattcgaaggcaaaaactgtgaattattca-
cac
ggaagctctgcagcctggacaacggggactgtgaccagttctgccacgaggaacagaactctgtggtgtgctcc-
tgc
gcccgcgggtacaccctggctgacaacggcaaggcctgcattcccacagggccctacccctgtgggaaacagac-
cct
ggaacgcaggaagaggtcagtggcccaggccaccagcagcagcggggaggcccctgacagcatcacatggaagc-
cat
atgatgcagccgacctggaccccaccgagaaccccttcgacctgcttgacttcaaccagacgcagcctgagagg-
ggc
gacaacaacctcacgcgtatcgtgggaggccaggaatgcaaggacggggagtgtccctggcaggccctgctcat-
caa
tgaggaaaacgagggtttctgtggtggaactattctgagcgagttctacatcctaacggcagcccactgtctct-
acc
aagccaagagattcaaggtgagggtaggtgaccggaacacggagcaggaggagggcggtgaggcggtgcacgag-
gtg
gaggtggtcatcaagcacaaccggttcacaaaggagacctatgacttcgacatcgccgtgctccggctcaagac-
ccc
catcaccttccgcatgaacgtggcgcctgcctgcctccccgagcgtgactgggccgagtccacgctgatgacgc-
aga
agacggggattgtgagcggcttcgggcgcacccacgagaagggccggcagtccaccaggctcaagatgctggag-
gtg
ccctacgtggaccgcaacagctgcaagctgtccagcagcttcatcatcacccagaacatgttctgtgccggcta-
cga
caccaagcaggaggatgcctgccagggggacagcgggggcccgcacgtcacccgcttcaaggacacctacttcg-
tga
caggcatcgtcagctggggagagggctgtgcccgtaaggggaagtacgggatctacaccaaggtcaccgccttc-
ctc
aagtggatcgacaggtccatgaaaaccaggggcttgcccaaggccaagagccatgccccggaggtcataacgtc-
ctc tccattgaaa (DNA sequence of modified human FX-type A; 1-1509
bp) SEQ ID NO: 7
Atggcgcacgtccgaggcttgcagctgcctggctgcctggccctggctgccctgtgtagccttgtgcacagcca-
gca
tgtgttcctggctcctcagcaagcacggtcgctgctccagcgggtccggcgagccaattcctttcttgaagaga-
tga
agaaaggacacctcgaaagagagtgcatggaagagacctgctcatacgaagaggcccgcgaggtctttgaggac-
agc
gacaagacgaatgaattctggaataaatacaaagatggcgaccagtgtgagaccagtccttgccagaaccaggg-
caa
atgtaaagacggcctcggggaatacacctgcacctgtttagaaggattcgaaggcaaaaactgtgaa.ttattc-
aca
cggaagctctgcagcctggacaacggggactgtgaccagttctgccacgaggaacagaactctgtggtgtgctc-
ctg
cgcccgcgggtacaccctggctgacaacggcaaggcctgcattcccacagggccctacccctgtgggaaacaga-
ccc
tggaacgcaggaagaggtcagtggcccaggccaccagcagcagcggggaggcccctgacagcatcacatggaag-
cca
tatgatgcagccgacctggaccccaccgagaaccccttcgacctgcttgacttcaaccagacgcagcctgagag-
ggg
cgacaacaacctcacgcgtatcgtgggaggccaggaatgcaaggacggggagtgtccctggcaggccctgctca-
tca
atgaggaaaacgagggtttctgtggtggaactattctgagcgagttctacatcctaacggcagcccactgtctc-
tac
caagccaagagattcaaggtgagggtaggtgaccggaacacggagcaggaggagggcggtgaggcggtgcacga-
ggt
ggaggtggtcatcaagcacaccaagttcgtgccccctaactactattacgtccaccagaattttgaccgggtgg-
cct
atgacttcgacatcgccgtgctccggctcaagacccccatcaccttccgcatgaacgtggcgcctgcctgcctc-
ccc
gagcgtgactgggccgagtccacgctgatgacgcagaagacggggattgtgagcggcttcgggcgcacccacga-
gaa
gggccggcagtccaccaggctcaagatgctggaggtgccctacgtggaccgcaacagctgcaagctgtccagca-
gct
tcatcatcacccagaacatgttctgtgccggctacgacaccaagcaggaggatgcctgccagggggacagcggg-
ggc
ccgcacgtcacccgcttcaaggacacctacttcgtgacaggcatcgtcagctggggagagggctgtgcccgtaa-
ggg
gaagtacgggatctacaccaaggtcaccgccttcctcaagtggatcgacaggtccatgaaaaccaggggcttgc-
cca aggccaagagccatgccccggaggtcataacgtcctctccattgaaa (DNA sequence
of modified human FX-type B; 1-1512 bp) SEQ ID NO: 8
atggcgcacgtccgaggcttgcagctgcctggctgcctggccctggctgccctgtgtagccttgtgcacagcca-
gca
tgtgttcctggctcctcagcaagcacggtcgctgctccagcgggtccggcgagccaattcctttcttgaagaga-
tga
agaaaggacacctcgaaagagagtgcatggaagagacctgctcatacgaagaggcccgcgaggtctttgaggac-
agc
gacaagacgaatgaattctggaataaatacaaagatggcgaccagtgtgagaccagtccttgccagaaccaggg-
caa
atgtaaagacggcctcggggaatacacctgcacctgtttagaaggattcgaaggcaaaaactgtgaattattca-
cac
ggaagctctgcagcctggacaacggggactgtgaccagttctgccacgaggaacagaactctgtggtgtgctcc-
tgc
gcccgcgggtacaccctggctgacaacggcaaggcctgcattcccacagggccctacccctgtgggaaacagac-
cct
ggaacgcaggaagaggtcagtggcccaggccaccagcagcagcggggaggcccctgacagcatcacatggaagc-
cat
atgatgcagccgacctggaccccaccgagaaccccttcgacctgcttgacttcaaccagacgcagcctgagagg-
ggc
gacaacaacctcacgcgtatcgtgggaggccaggaatgcaaggacggggagtgtccctggcaggccctgctcat-
caa
tgaggaaaacgagggtttctgtggtggaactattctgagcgagttctacatcctaacggcagcccactgtctct-
acc
aagccaagagattcaaggtgagggtaggtgaccggaacacggagcaggaggagggcggtgaggcggtgcacgag-
gtg
gaggtggtcatcaagcacaagaaattcgtgccccctaagaaaagccaggagttctacgaaaagtttgacctggt-
ctc
ctatgacttcgacatcgccgtgctccggctcaagacccccatcaccttccgcatgaacgtggcgcctgcctgcc-
tcc
ccgagcgtgactgggccgagtccacgctgatgacgcagaagacggggattgtgagcggcttcgggcgcacccac-
gag
aagggccggcagtccaccaggctcaagatgctggaggtgccctacgtggaccgcaacagctgcaagctgtccag-
cag
cttcatcatcacccagaacatgttctgtgccggctacgacaccaagcaggaggatgcctgccagggggacagcg-
ggg
gcccgcacgtcacccgcttcaaggacacctacttcgtgacaggcatcgtcagctggggagagggctgtgcccgt-
aag
gggaagtacgggatctacaccaaggtcaccgccttcctcaagtggatcgacaggtccatgaaaaccaggggctt-
gcc caaggccaagagccatgccccggaggtcataacgtcctctccattgaaa SEQ ID NO: 9
1 kkfvppkksqefyekfdlaay SEQ ID NO: 10 1 kkfvppnyyyvhqnfdlaay SEQ ID
NO: 11 1 kkfvppqkaykfdlaay
BRIEF DESCRIPTION OF THE DRAWINGS
[0085] FIG. 1: Blood coagulation FXa structure. Panel A: Schematic
.gamma.-carboxyglutamic ("GLA") EGF-1 and -2 ("EGF"), and serine
protease domain ("SP") structure of coagulation FXa. Panel B:
Crystal structure of the human FXa serine protease (pdb 2W26).
Indicated are the catalytic triad His-276, Asp-322, Ser-419,
rivaroxaban/apixaban contact residues Try-319 and Phe-396, position
of residues 316-317 (in spheres), and residues Gly-289, Glu-297,
Val-305, and His-311. Panel C: Alignment of region 311-322 in
various plasma FX species with conserved residues (highlighted),
contact residue Tyr-319, and catalytic residue Asp-322 indicated
(SEQ ID NOS.1 and 29-36). *Indicates venom coagulation FX with
insertion in the region corresponding to the region between Gly-289
and Asp-320 of SEQ ID NO:1.
[0086] FIGS. 2A-2C: Inhibition of chromogenic FXa activity by
direct FXa inhibitors.
[0087] FIG. 2A: Peptidyl substrate conversion (SpecFXa, 250 .mu.M)
by recombinant human coagulation FXa (hFXa, 2 nM, circles) or venom
P. textilis coagulation FXa (vptFXa, 10 nM, triangles) in the
presence of increasing concentrations (1 nM-10 .mu.M) rivaroxaban
("riva," closed symbols) or apixaban ("api," open symbols).
Substrate conversion is plotted as the % of incubations in the
absence of inhibitor. FIGS. 2B and 2C: Thrombin generation in
coagulation FX-deficient plasma was initiated with 0.5 nM hFXa
(FIG. 2B) or vptFXa (FIG. 2C) in the absence (grey line/grey
column) or presence of 0.4 .mu.M rivaroxaban ("riva," black
line/black column) or 2 .mu.M apixaban ("api," dotted line/white
column). Thrombin formation was assessed using a fluorogenic
substrate and peak thrombin concentrations of the various
incubations are shown in the insets.
[0088] FIGS. 3A and 3B: FIG. 3A: Fluorescent Western blot of
recombinant FX (200 ng) obtained from HEK293 cell lines that stably
express either recombinant human FX (r-hFX, lane 1, 5), modified
human FX-A (mod A, lane 2, 6) or modified human FX-B (mod B, lane
3, 7), before (lanes 1, 2, 3) or after (lanes 5, 6, 7) incubation
with RVV-X activator. The heavy chain of endogenous plasma-derived
human FXa migrates at .about.29 kDa (lane 9). Relative weight (kDa)
of the protein markers (lanes 4, 8) are indicated. FIG. 3B:
Recombinant FX in conditioned media from HEK293 cell lines stably
expressing either recombinant human FX (black column), modified
human FX-A (white column) or modified human FX-B (grey column) was
quantified using an FX-specific ELISA. Each individual bar
represents a single stable cell line with the highest attainable
expression per FX variant.
[0089] FIG. 4: Macromolecular substrate activation. Prothrombin
conversion (1.4 .mu.M) in the presence of 50 .mu.M PCPS, 20 nM FV
(FV810, recombinant B-domain truncated FV) and 0.1 nM of modified
human coagulation FXa type A (m-hFXa A), type B (m-hFXa B),
recombinant (r-hFXa), or plasma-derived (pd-hFXa) FXa. The
substrate conversion is plotted in nM/min/nM Enzyme and data are
the mean value of two independent experiments.+-.S.D.
[0090] FIGS. 5A and 5B: Inhibition of FXa chimer type-A by DFXIs.
Peptidyl substrate conversion (SpecFXa, 250 .mu.M) of RVV-X
activated modified human coagulation FXa type A (m-hFXa A, 1 nM) in
comparison to recombinant human coagulation FXa (r-hFXa, 3 nM),
plasma-derived human coagulation FXa (pd-FXa, 2 nM), and venom P.
textilis (vptFXa, 1 nM) FXa. Conversion rates were determined in
the presence of 0.001-100 .mu.M of Rivaroxaban (FIG. 5A) or
Apixaban (FIG. 5B). The data represent the mean value of two
independent experiments, except for r-hFXa (n=1).
[0091] FIGS. 6A and 6B: Inhibition of modified human FX-A and
modified human FX-B by DFXIs. Peptidyl substrate conversion
(SpecFXa, 250 .mu.M) by RVV-X activated modified human FX-A (m-hFXa
A, 1 nM) and modified human FX-B (m-hFXa B, 7 nM), in comparison to
RVV-X-activated recombinant human coagulation FXa (r-hFXa, 6 nM).
Conversion rates were determined in the presence of 0.001-100 .mu.M
of rivaroxaban (FIG. 6A) and apixaban (FIG. 6B). The data are the
means of two independent experiments.
[0092] FIGS. 7A and 7B: Inhibition of modified human FX-A or
modified human FX-B by DFXIs in the presence of cofactor Va and
phospholipids. Peptidyl substrate conversion (SpecFXa, 250 .mu.M)
by RVV-X activated modified human FX-A (m-hFXa A, 2 nM) and
activated modified human FX-B (m-hFXa B, 4 nM) in comparison to by
RVV-X activated recombinant human coagulation FXa (r-hFXa, 3 nM),
in the presence of 50 .mu.M PCPS and 30 nM FV (FV810, recombinant
B-domain truncated). Conversion rates were determined in the
presence of 0.001-100 .mu.M of Rivaroxaban (FIG. 7A) or Apixaban
(FIG. 7B). The data are the means of two independent
experiments.
[0093] FIGS. 8A-8C: Multiple alignment of coagulation FX proteins
of different species. The amino acid sequence of human coagulation
FX (Genbank Accession No.: AAH46125.1) (HUM) (SEQ ID NO:1) is
compared to the amino acid sequences of M. musculus coagulation FX
(Genbank Accession No.: AAC36345.1) (MUS) (SEQ ID NO:29), X.
tropicalis coagulation FX (Genbank Accession No.: NP001015728)
(Xtr) (SEQ ID NO:30), D. rerio coagulation FX (Genbank Accession
No.: AAM88343.1) (Dre) (SEQ ID NO:31), T. rubripes coagulation FX
(Genbank Accession No.: NP001027783.1) (Tru) (SEQ ID NO:32), P.
textilis coagulation FX isoform 1 (UniprotKB accession No.: Q1L659)
(Pte1) (SEQ ID NO:33), P. textilis coagulation FX isoform 2
(UniprotKB accession No.: Q1L658) (Pte2) (SEQ ID NO:34), P.
textilis coagulation FX (pseutarin C catalytic subunit precursor;
Genbank Accession No.: AAP86642.1) (Pte3) (SEQ ID NO:35) and N.
scutatus coagulation FX (UniProtKB accession No.: P82807.2) (Nsc)
(SEQ ID NO:36). In these figures, Gly-289, Asp-320, Tyr-319,
Glu-297, Val-305 and His-311 of SEQ ID NO:1 are indicated in bold
and are underlined. These figures show that there is variation in
the region of amino acid residues corresponding to the region
between Gly-289 and Asp-320 of SEQ ID NO:1 between coagulation FX
proteins of different species. Amino acid residues that are
conserved in all species are indicated in the consensus
sequence.
[0094] FIG. 9: Amino acid composition of endogenous hFX and
chimeric FX variants. Serine protease domain residues Histidine91
and Tyrosine99 (chymotrypsin numbering; corresponding to His 311
and Tyrosine 319, respectively, of FX as depicted in SEQ ID NO:1)
of endogenous human (hFX) in alignment with chimeric FX type A
(c-FX A, middle; sequence between His 311 and Asp 320 corresponds
to SEQ ID NO:9), type B (c-FX B; sequence between His 311 and Asp
320 corresponds to SEQ ID NO:10), and type C (c-FX C; sequence
between His 311 and Asp 320 corresponds to SEQ ID NO:11).
[0095] FIG. 10: Characterization of FXa: Panel A: Coomassie
staining of 5 .mu.g FXa variants on 4-12% Bis-Tris gels. From left
to right: plasma-derived Factor Xa (pd-FXa), r-hFXa, chimeric
factor Xa type A, B and C (-A, -B, -C). Panel B: Prothrombin
conversion (1.4 .mu.M) in the presence of 50 .mu.M PCPS (75%
phosphatidylcholine, 25% phosphatidylserine) and 20 nM FV (FV810,
recombinant B-domain truncated FV) and 0.1 nM of pd-FXa, r-hFXa,
c-FXa-A, c-FXa-B and c-FXa-C. Data points are the mean value of two
independent experiments.
[0096] FIG. 11: Inhibition of FXa variants by DOACs. Normalized
prothrombin conversion by 1 nM of pd-FXa (triangles), r-hFXa
(circles), chimeric FXa-A (squares), -B (diamonds) and -C (crosses)
was assessed in the presence of 0.001-100 .mu.M of Apixaban (left,
closed symbols) or Edoxaban (right, open symbols). Inhibitory
constants (determined with Graphpad Prism 6 software suite) of
Apixaban for pd-FXa: 2 nM, r-hFXa: 4 nM, c-FXa-A: 130 nM, -B: 760
nM-C: 1270 nM and of Edoxaban for r-hFXa: 0.5 nM, c-FXa-A: 3 nM,
-B: 140 nM-C: 270 nM.
[0097] FIGS. 12A and 12B: FXa-initiated thrombin generation (TG)
profiles for FXa variants. Plasma TG in the absence (FIG. 12A) and
presence (FIG. 12B) of DOAC Apixaban (2 Initiation of TG by pd-FXa,
r-hFXa, c-FXa-A, c-FXa-B and c-FXa-C in FX-depleted plasma. Curves
are the average of at least three independent experiments.
[0098] FIGS. 13A and 13B: Tissue factor (TF)-initiated TG profile
for r-hFX and c-FX-C. FIG. 13A: Plasma TG at low TF (2 pM) in the
absence and presence of 2 .mu.M DOAC Apixaban (Apixa) by 1 unit
r-hFX, r-hFX plus Apixaban, c-FXa-C or c-FXa-C plus Apixaban. One
unit of r-hFX (7 .mu.g/ml) or c-FXa-C (16 .mu.g/ml) was defined by
a prothrombin time-based clotting assay using normal human plasma
as reference. Curves represent the average of at least three
independent experiments. FIG. 13B: Plasma TG at high TF (20
pM).
[0099] FIGS. 14A and 14B: TF-initiated TG profile for r-hFX and
c-FX-C. (Upper graph): Plasma TG at low TF (2 pM) in the absence
(dotted line) and presence of 200 nM (light grey), 600 nM (dark
grey) and 2000 nM (black) DOAC Edoxaban by 1 unit r-hFX (7
.mu.g/ml). (Lower graph): Plasma TG at low TF (2 pM) with similar
concentrations of Edoxaban by 1 unit of c-FXa-C (16 .mu.g/ml).
Curves represent the average of two independent experiments.
TABLE-US-00002 [0100] TABLE 1 Side-chain Side-chain charge
Hydropathy Absorbance .epsilon. at .lamda.max (.times.10.sup.-3
M.sup.-1 Amino Acid 3-Letter.sup.(114) 1-Letter.sup.(114)
polarity.sup.(114) (pH 7.4).sup.(114) Index.sup.(115)
.lamda.max(nm).sup.(116) cm.sup.-1).sup.(116) Alanine Ala A
nonpolar neutral 1.8 Arginine Arg R Basic polar positive -4.5
Asparagine Asn N polar neutral -3.5 Aspartic acid Asp D acidic
polar negative -3.5 Cysteine Cys C nonpolar neutral 2.5 250 0.3
Glutamic acid Glu E acidic polar negative -3.5 Glutamine Gln Q
polar neutral -3.5 Glycine Gly G nonpolar neutral -0.4 Histidine
His H Basic polar positive (10%) -3.2 211 5.9 neutral (90%)
Isoleucine Ile I nonpolar neutral 4.5 Leucine Leu L nonpolar
neutral 3.8 Lysine Lys K Basic polar positive -3.9 Methionine Met M
nonpolar neutral 1.9 Phenylalanine Phe F nonpolar neutral 2.8 257,
200, 188 0.2, 9.3, 00.0 Proline Pro P nonpolar neutral -1.6 Serine
Ser S polar neutral -0.8 Threonine Thr T polar neutral -0.7
Tryptophan Trp W nonpolar neutral -0.9 280, 219 5.6, 47.0 Tyrosine
Tyr Y polar neutral -1.3 274, 222, 193 1.4, 8.0, 48.0 Valine Val V
nonpolar neutral 4.2
DETAILED DESCRIPTION
Examples
Example 1
Materials and Methods
[0101] Rivaroxaban and Apixaban were obtained from Alsachim
(Illkirch, France) and dissolved in DMSO (.about.30 mg/ml). The
peptidyl substrate
methoxycarbonylcyclohexylglycylglycylarginine-p-nitroanilide
(Spec-Xa) was obtained from Sekisui Diagnostics (Stamford, Conn.,
USA). All tissue culture reagents were from Life Technologies
(Carlsbad, Calif.), except insulin-transferrin-sodium selenite
(ITS), which was from Roche (Basel, Switzerland). Small unilamellar
phospholipid vesicles (PCPS) composed of 75% (w/w) hen egg
L-phosphatidylcholine and 25% (w/w) porcine brain
L-phosphatidylserine (Avanti Polar Lipids, Alabaster, Ala.) were
prepared and characterized as described previously (Higgins et al.,
J. Biol. Chem. 1983, 258:6503-6508). FX-depleted human plasma was
obtained from Diagnostica Stago (Paris, France). All functional
assays were performed in HEPES buffered Saline (20 mM Hepes, 0.15 M
NaCl, pH 7.5) supplemented with 5 mM CaCl2 and 0.1% polyethylene
glycol 8000 (assay buffer). Mammalian expression vector pCMV4
(Andersson et al., J. Biol. Chem. 1989, 264:8222-8229), carrying
recombinant human FX (r-hFX) was a generous gift from Rodney M.
Camire (Camire et al., Biochemistry 2000, 39:14322-14329). The
pcDNA3 vector was obtained from Invitrogen and the PACE cDNA was a
generous gift from Genetics Institute, Boston, Mass. A vector
carrying Furin proprotein convertase has been described (U.S. Pat.
No. 5,460,950).
[0102] Human recombinant Factor V (FV) was prepared, purified, and
characterized as described previously (Bos et al., Blood 2009,
114:686-692). Recombinant P. textilis venom FXa (vpt-FXa) was
prepared, purified, and characterized as described previously
(Verhoef et al., Toxin Reviews) (2013)
(doi:10.3109/15569543.2013.844712). Plasma-derived human Factor Xa
(pd-hFXa), DAPA, human prothrombin and Anti-Human Factor X
monoclonal mouse IgG (AHX-5050) were from Haematologic Technologies
(Essex Junction, Vt., USA). FX antigen paired antibodies for ELISA
were obtained from Cedarlane (Burlington, Canada). RVV-X activator
was obtained from Diagnostica Stago (Paris, France), or
Haematologic Technologies. Restriction endonuclease Apa1 was
obtained from New England Biolabs (Ipswich, Mass., USA). T4-DNA
ligase was obtained from Roche (Roche Applied Science,
Indianapolis, Ind., USA).
[0103] The DNA sequence encoding modified human FX-A is provided as
SEQ ID NO:7. The DNA sequence encoding modified human FX-B is
provided as SEQ ID NO:8. Nucleotides encoding SEQ ID NO:4 (to
generate modified human FX-A) or SEQ ID NO:5 (to generate modified
human FX-B) sequences flanked by ApaI restriction sites were
synthesized by Genscript (Piscataway, N.J., USA), subcloned into
pCMV4 mammalian expression vector using Apa1 and T4-DNA ligase and
sequenced for consistency. Modified human FX-A and modified human
FX-B are also referred to as mod-hFX-A and mod-hFX-B, respectively.
Stable HEK293 cell lines expressing r-hFX or modified hFX were
obtained as described previously (Larson et al., Biochemistry 1998,
37:5029-5038). HEK293 cells were cotransfected with pCMV4 and
pcDNA-PACE vectors using Lipofectamine2000 according to the
manufacturer's instructions. FX expression of transfectants was
assessed by a modified one-step clotting assay using FX-depleted
human plasma. Transfectants with the highest expression levels were
expanded into T175 culture flasks and conditioned for 24 hours on
expression media (DMEM-F12 nutrient mixture without Phenol-red
supplemented with: Penicillin/Streptomycin/Fungizone, 2 mM
L-glutamine, 10 .mu.g/ml ITS, 100 .mu.g/ml Geneticin-418 sulphate
and 6 .mu.g/ml vitamine K). Conditioned media was collected,
centrifuged at 10,000 g to remove cellular debris, concentrated in
a 10-kDa cut-off filter (Millipore, Darmstadt, Germany), washed
with HEPES-buffered saline and stored in 50% glycerol at
-20.degree. C. FX antigen levels of glycerol stocks were assessed
by sandwich ELISA according to the manufacturer's instructions
using human pooled plasma as reference, assuming a plasma FX
concentration of 10 .mu.g/ml.
[0104] Expression media was conditioned for 24 hours on stable cell
lines expressing either r-hFX, modified human FX-A or modified
human FX-B. An aliquot of conditioned media was incubated with
RVV-X (10 ng/.mu.1; Haematologic Technologies) for 120 minutes at
37.degree. C. After activation, modified human FX-A or modified
human FX-B are also referred to as m-hFXa A or m-hFXa B,
respectively. Assuming similar substrate affinities for all FXa
variants, the concentration of FXa in media was subsequently
determined by peptidyl substrate conversion (Spec-Xa, 250 .mu.M)
using known concentrations of pd-hFXa as reference. Steady-state
initial velocities of macromolecular substrate cleavage were
determined discontinuously at 25.degree. C. as described (Camire,
J. Biol. Chem. 2002, 277:37863-70). Briefly, progress curves of
prothrombin activation were obtained by incubating PCPS (50 .mu.M),
DAPA (10 .mu.M), and prothrombin (1.4 .mu.M) with human recombinant
FV-810 (B-domain truncated, constitutively active), and the
reaction was initiated with either 0.1 nM of pd-hFXa, r-hFXa,
m-hFXa B, or 0.033 nM of m-hFXa A. The rate of prothrombin
conversion was measured as described (Krishnaswamy et al.,
Biochemistry 1997, 36:3319-3330).
[0105] Recombinant FX and modified human FX-A and modified human
FX-B (200 ng) were activated by RVV-X (0.5 U/ml) for 60 minutes at
37.degree. C. and subjected to electrophoresis under reducing (30
mM dithiothreitol) conditions using pre-cast 4-12% gradient gels
and the MES buffer system (Life Technologies) and transferred to a
nitrocellulose membrane using the Trans-Blot Turbo Transfer System
(Bio-Rad Laboratories, Hercules, Calif., USA). The blot was probed
with an anti-heavy chain FX antibody and protein bands were
visualized using a Dyelight-800 anti-mouse fluorescent antibody
(Thermo Scientific, Rockford, Ill. USA). Plasma-derived hFXa (200
ng) was used as a reference.
[0106] Thrombin generation was adapted from protocols earlier
described (Hemker et al., Pathophysiol. Haemost. Thromb. 2003,
33:4-15). Briefly, FX-depleted plasma was mixed with Corn Trypsin
Inhibitor (70 .mu.g/ml), buffer (25 mM HEPES, 175 mM NaCl, 5 mg/ml
BSA, pH 7.5) and PCPS (20 .mu.M) and incubated for 10 minutes at
37.degree. C. in a 96-well microplate. Thrombin formation was
initiated by addition of pd-hFXa (0.5 nM) or vpt-FXa (0.5 nM)
preincubated with Rivaroxaban (0.4 .mu.M) or Apixaban (0.2
supplemented with FluCa and immediately transferred to the plasma
mix. The final reaction volume was 120 of which 64 .mu.l was
FX-depleted plasma. Thrombin formation was determined every 20
seconds for 30 minutes and corrected for the calibrator using a
software suite (Thrombinoscope, version 5.0). The mean endogenous
thrombin potential (the area under the thrombin generation curve)
was calculated from at least two individual experiments. Calibrator
and fluorescent substrate (FluCa) were purchased from
Thrombinoscope (Maastricht, The Netherlands).
[0107] Peptidyl substrate conversion (Spec-Xa, 250 .mu.M final) of
each FXa variant was performed in the absence or presence of direct
FXa inhibitors Rivaroxaban and Apixaban (0.001 .mu.M-100 .mu.M
final) at ambient temperature. Calcium-free stocks of pd-hFXa (2 nM
final) or vpt-FXa (10 nM final) were diluted in assay buffer and
incubated in a 96-well microplate in the presence of assay buffer
or inhibitor for 2 minutes. Substrate conversion was initiated with
Spec-Xa and absorption was monitored for 10 minutes at 405 nM in a
SpectraMax M2e microplate reader equipped with the Softmax Pro
software suite (Molecular Devices, Sunnyvale, Calif., USA). In
order to assay DFXI sensitivity of each recombinant FX variant,
glycerol stocks (5-40 .mu.l) of r-hFX, modified human FX-A and
modified human FX-B were diluted in assay buffer and incubated with
RVV-X (0.5 U/ml) for 60 minutes at 37.degree. C. Activated stocks
were subsequently diluted in assay-buffer, incubated for 2 minutes
in a 96-well microplate in the presence of assay buffer or
inhibitor and assayed for substrate conversion as described. The
relative concentration of rhFX, m-hFXa A and m-hFXa B was assessed
from the rate of substrate conversion in the absence of inhibitor
using known concentrations of pd-hFXa as reference.
Results
[0108] Venom-Derived P. textilis (Vpt)-FXa is Resistant to
Inhibition by DFXIs
[0109] Biochemical characterization of purified recombinant
venom-derived P. textilis FXa (vptFXa) revealed that this protease,
unlike any other FXa species known to date, is resistant to
inhibition by the direct anticoagulants rivaroxaban and apixaban,
which have been designed to reversibly block the active site of
FXa. Consistent with previous observations, the Ki for human FXa
(hFXa) inhibition was approximately 1 nM (Perzborn, J. Thromb.
Haemost. 2005, 3:514-521), whereas vptFXa inhibition was at least a
1000-fold reduced (FIG. 2A). These findings were corroborated in a
plasma system mimicking in vivo fibrin generation, demonstrating
that physiological concentrations of the FXa inhibitors hardly
affected vptFXa-initiated thrombin formation, while a significant
reduction was observed with hFXa present (FIGS. 2B and 2C).
Human-Venom P. textilis FXa Chimeras
[0110] A striking structural element that is not only limited to
vptFXa, but also present in venom FX from the Australian snake
Notechis scutatus, is an altered amino acid composition at a
position close to the hFXa active site (FIG. 1, Panel C). Given its
location, it was hypothesized that this unique helix may not only
modulate the interaction with rivaroxaban and/or apixaban, but also
with FVa, as the FVa binding site is C-terminal to this helix (Lee
et al., J. Thromb. Haemost. 2011, 9:2123-2126). To test this
hypothesis, the two-protein coding DNA constructs as listed in SEQ
ID NOS:7 and 8 were prepared. The mod-hFX-A chimera as provided in
SEQ ID NO:7 comprises the relevant part of the N. scutatus DNA
sequence (indicated in bold and underlined) and the mod-hFX-B
chimera as provided in SEQ ID NO:8 comprises the relevant part of
the P. textilis sequence (indicated in bold and underlined).
[0111] Using these DNA constructs, HEK293 cell lines were generated
that stably produced both chimeric proteins and subsequently
assessed the expression levels of modified human FX from HEK293
cells by conditioning the cells on expression media for 24 hours.
Western blot analysis revealed expression of full-length FX for
both chimeric variants similar to wild-type FX (FIG. 3A).
Incubation with activator from Russell's Viper Venom (RVV-X)
resulted in proteolytic activation of approximately 30% of zymogen
FX to FXa, indicated by the appearance of the .about.29 kDa heavy
chain band. The heavy chain of both modified human FXa-A and
modified human FXa-B migrated at a slightly higher molecular
weight, which is consistent with the insertion of a snake sequence
that is 12 or 13 residues longer as compared to that of human FXa,
respectively. Analysis of the FX antigen levels in conditioned
media indicated that whereas the expression of mod-hFX-A was
approximately seven-fold reduced, that of mod-hFX-B was similar to
wild-type human FX (FIG. 3B). The low FX antigen levels of
mod-hFX-A correlated with the similarly low FX activity levels
observed employing a modified clotting assay. This indicates that
while the protein expression of mod-hFX-A is suboptimal as compared
to that of the other FX variants, its FX function is not
perturbed.
[0112] To test zymogen activation of FX, rFX and modified human
FX-A and modified human FX-B was converted to FXa using FX
activator from Russell's Viper Venom (RVV-X). Both modified human
FXa-A and modified human FXa-B displayed protease activity upon
RVV-X activation, as assessed by conversion of the small
FXa-specific peptidyl substrate SpectroZyme Xa. In addition, the
prothrombin conversion rates in the presence of the human cofactor
FVa of both chimeras were similar to human FXa (both pd-hFXa and
r-hFXa) (FIG. 4). Collectively, these observations suggest that the
snake sequence insertions do not severely hamper the enzymatic
properties of human FX.
Inhibition of FXa Chimeras by DFXIs
[0113] To estimate the inhibitory constant (Ki) of Rivaroxaban and
Apixaban for RVV-X activated modified human FX-A, the activated
recombinant protein was pre-incubated with 0.001 to 100 .mu.M of
inhibitor and subsequently assayed for its catalytic activity
toward SpectroZyme Xa. While incubation with 0.5 .mu.M Rivaroxaban
resulted in full inhibition of r-hFXa and pd-hFXa, mod-hFXa-A
remained fully active under these conditions (FIG. 5A). Moreover,
the chimeric variant still displayed partial chromogenic activity
following incubation with 100 .mu.M Rivaroxaban, similar to the P.
textilis venom FXa. These data indicate that the Ki for inhibition
of mod-hFXa-A is at least 100-fold increased as compared to that of
human FXa. A similar reduced sensitivity for inhibition by Apixaban
was observed (FIG. 5B).
[0114] Assessment of the inhibition of mod-hFXa-B by rivaroxaban
and apixaban resulted in a Ki similar to that observed for
mod-hFXa-A (FIGS. 6A and 6B). Thus, a reduced sensitivity for
inhibition by apixaban and rivaroxaban was shown. Finally,
DFXI-inhibition of the chimeric FXa variants was not altered in the
presence of the cofactor FVa and negatively charged phospholipid
vesicles, suggesting that both the free protease as well as that
assembled into an FVa-FXa-lipid-bound complex are equally resistant
to inhibition by Rivaroxaban and Apixaban (FIGS. 7A and 7B).
Example 2
Materials and Methods
[0115] Unless indicated otherwise, materials and methods as used in
this example were the same or similar to the materials and methods
indicated in Example 1.
[0116] Construction and expression of recombinant FX: DNA encoding
chimeric FX-A (c-FX A), chimeric FX-B (c-FX B) and chimeric FX-C
(c-FX C) were synthesized at Genscript (Piscataway, N.J., USA),
subcloned into pCMV4 mammalian expression vector using Apa1 and
T4-DNA ligase and sequenced for consistency. Stabile HEK293 cell
lines expressing recombinant human or recombinant chimeric FX were
obtained as described previously (Larson et al., Biochemistry 1998,
37:5029-5038). HEK293 cells were cotransfected with pCMV4 and
pcDNA-PACE vectors by LIPOFECTAMINE.RTM. 2000 according to the
manufacturer's instructions.
[0117] Purification of chimeric FX(a): Recombinant chimerix FX
products A, B and C were prepared, purified and characterized as
described previously (Camire et al., 2000), with the exception that
the immunoaffinity purification was replaced by a calcium gradient
purification of FX on a POROS HQ20-sepharose column. The typical
yield of fully .gamma.-carboxylated recombinant FX was 0.9 mg/liter
conditioned medium. Purified recombinant chimeric FX was activated
with RVV-X (0.1 U/mg FX), isolated by size-exclusion chromatography
on a Sephacryl 5200 HR column (Vt 460 ml) and stored at -20.degree.
C. in HBS containing 50% vol/vol glycerol. Purified products were
visualized by Coomassie staining.
[0118] Macromolecular substrate activation: Steady-state initial
velocities of macromolecular substrate cleavage were determined
discontinuously at 25.degree. C. as described (Camire, 2002).
Briefly, progress curves of prothrombin activation were obtained by
incubating PCPS (50 .mu.M), DAPA (10 and prothrombin (1.4 .mu.M)
with human recombinant FV-810 (20 nM, B-domain truncated,
constitutively active FV), and the reaction was initiated with
either 0.1 nM of pd-hFXa, r-hFXa, c-FXa A, c-FXa B or c-FXa C. The
rate of prothrombin conversion was measured as described
(Krishnaswamy et al., 1997). Prothrombin conversion was assayed in
absence or presence of direct FXa inhibitors Edoxaban (CAS Registry
Number 912273-65-5; manufactured by Daiichi Sankyo, marketed as
Savaysa) and Apixaban (0.001 .mu.M-100 final) in order to determine
DOAC sensitivity of each recombinant FXa variant.
[0119] Thrombin generation assays: Thrombin generation was adapted
from protocols earlier described (Hemker et al., 2003). Briefly,
thrombin generation curves were obtained by supplementing
FX-depleted plasma with Tissue Factor (TF, 2 or 20 pM final), Corn
Trypsin Inhibitor (70 .mu.g/ml), PCPS (20 .mu.M) and 1 Unit
(prothrombin time-specific clotting activity) of r-hFX (7 .mu.g/ml)
or chimeric FX-C (16 .mu.g/ml). Thrombin formation was initiated by
adding Substrate buffer (Fluca) to the plasma. FXa thrombin
generation curves were obtained by supplementing FX-depleted plasma
with Corn Trypsin Inhibitor (70 .mu.g/ml), assay buffer and PCPS
(20 Thrombin formation was initiated by addition of FXa premixed
with Rivaroxaban or Apixaban, assay buffer without calcium and
supplemented with Fluca. The final reaction volume was 120 of which
64 .mu.l was FX-depleted plasma. Thrombin formation was determined
every 20 seconds for 30 minutes and corrected for the calibrator,
using the software of Thrombinoscope. The lag time, mean endogenous
thrombin potential (the area under the thrombin generation curve),
time to peak and peak thrombin generation, was calculated from at
least three individual experiments.
Results
[0120] The 9-13 residue insertion in the serine protease domains of
P. textilis venom, P. textilis isoform and N. scutatis venom FXa
has prompted construction of chimeras of human and snake FX. Three
protein coding DNA constructs were made that incorporate each of
these insertions in human FXa (FIG. 9). Using these DNA constructs,
HEK293 cell lines were generated that stably produce either
recombinant normal human FX (r-hFX) or three types of chimeric FX
(c-FX A, c-FX B and c-FX C). Expression levels of recombinant human
and chimeric FX from HEK293 cells were determined by culturing the
cells on expression media for 24 hours after which the clotting
activity of conditioned medium was assessed by a modified one-step
PT clotting assay in FX-depleted plasma. Recombinant
.gamma.-carboxylated FX was purified from conditioned media by
successive ion-exchange chromatography steps. A fraction of the FX
pool was subsequently activated with the FX activator from
Russell's Viper venom, isolated by size-exclusion chromatography
and characterized by SDS-PAGE. The heavy chain of purified
plasma-derived factor Xa migrates as a 50/50 mixture of FXa-.alpha.
and FXa-.beta. at .about.34-31 kDa. While autoproteolytic excision
of the C-terminal portion of FXa-.alpha. (residues 436-447) yields
the .beta. form of FXa, both isoforms are functionally similar with
respect to prothrombinase assembly, prothrombin activation,
antithrombin recognition, and peptidyl substrate conversion
(Pryzdial and Kessler, 1996).
[0121] The purified products of r-hFXa and chimeric FXa-B and -C
migrated predominantly as FXa-.beta., chimeric FXa-A migrates as a
50/50 mixture of .alpha. and .beta. FXa instead (FIG. 10, Panel A).
Kinectis of macromolecular substrate activation by r-hFXa and
chimeric FXa (A/B/C) on negatively charged phospholipid vesicles
(PCPS) in the presence of the cofactor FVa shows that all chimeric
variants assemble into the prothrombinase complex. However, the
catalytic rate of chimeric FXa variants-A, -B and -C is
respectively 8.2-, 6.8-, and 2.3-fold reduced compared to
recombinant human FXa. Furthermore, recombinantly prepared human
FXa shows a modest decrease in catalytic efficiency compared to
plasma-derived FXa (FIG. 10, Panel B).
[0122] To determine the inhibitory constant (Ki) of DOACs
(Apixaban, Edoxaban) for chimeric FXa (A/B/C), the kinetics of
prothrombin activation in the presence of 0.001 to 100 .mu.M of
DOAC was assayed. While plasma-derived FXa and recombinant human
FXa are fully inhibited at near equimolar concentrations of DOAC,
all chimeric FXa variants were able to sustain prothrombin
conversion at significantly higher FXa-inhibitor concentrations (Ki
Apixaban:130-1270 nM, Ki Edoxaban: 3-270 nM) (FIG. 11). Given that
the chimeric FXa variants comprise similarly positioned insertions
with a varying length and composition of amino acids, the close
proximity of these insertions to the DOAC-coordinating residue
Tyr99 and/or the active site was speculated to be of direct
consequence to the decreased sensitivity for the DOACs.
[0123] In order to assess the potential of chimeric FXa to restore
thrombin generation in DOAC-spiked plasma, a thrombin generation
(TG) assay was performed. FXa-initiated (5 nM) thrombin generation
in FX-depleted human plasma demonstrated a normal TG profile for
c-FXa variant C, and near normal profiles for c-FXa variants A and
B (FIG. 12A). While Apixaban (2 .mu.M) dramatically prolonged the
lag time and reduced peak thrombin generation in pd-FXa- and
r-hFXa-initiated TG, these parameters were unperturbed with the
chimeric FXa variants present (FIG. 12B) (Table 2). These results
show that chimeric FXa variants are able to restore hemostasis in
DOAC-inhibited plasma. In addition, the zymogen form of chimeric
FX-C is also able to sustain thrombin generation in FX-depleted
plasma. Initiation of coagulation by a low Tissue Factor (TF, 2 pM)
concentration generates a robust TG curve for chimeric FX-C that is
not affected by Apixaban, unlike TG by r-hFX (FIG. 13A). At low TF
concentration, chimeric FX-C displays a short delay in the onset of
TG and time to peak; in addition, chimeric FX-C has a larger
endogenous thrombin potential (ETP) and higher peak thrombin
generation (Table 3). However, these values normalize at high TF
(20 pM) concentrations (FIG. 13B) (Table 3). Based on the
observations made in the FXa-initiated TG assay, it is expected
that zymogen forms of chimeric FX variants A and B also sustain
TF-initiated TG in DOAC-spiked plasma. FIGS. 14A and 14B, in
combination with Table 4, provide further evidence the effect of
chimeric FXa variants on restoring hemostasis in DOAC-inhibited
plasma. Taken together, these results show that chimeric FX(a) is
able to restore hemostasis in DOAC-inhibited plasma, both in
zymogen and protease form
TABLE-US-00003 TABLE 2 Effect of Apixaban on FXa-initiated TG
parameters. Values represent experimental TG values obtained in the
presence of Apixaban corrected for TG values obtained inthe absence
of Apixaban. pd-FXa r-hFXa c-FXa -A c-FXa -B c-FXa -C Lagtime
arrest 299 293 61 12 3 (seconds) Delay in time to 515 467 120 30 7
peak (seconds) Peak Thrombin 26 33 78 85 99 Generation (% of no
Apixaban) Area under the 67 76 89 92 101 curve (% of no
Apixaban)
TABLE-US-00004 TABLE 3 Summary of low and high TF-initiated TG
experiments. r-hFX + c-FX -C + r-hFX + c-FX -C + Low TF (2 pM)
r-hFX Apixaban c-FX -C Apixaban High TF (20 pM) r-hFX Apixaban c-FX
-C Apixaban Lagtime 132 .+-. 5 696 .+-. 162 185 .+-. 12 186 .+-. 6
Lagtime 48 .+-. 1 138 .+-. 12 72 .+-. 2 78 .+-. 2 (seconds)
(seconds) Time to peak 324 .+-. 6 no peak 480 .+-. 24 492 .+-. 23
Time to peak 114 .+-. 6 804 .+-. 36 138 .+-. 6 144 .+-. 9 (seconds)
(seconds) Peak thrombin 61 .+-. 4 8 .+-. 4 78 .+-. 1 72 .+-. 4 Peak
thrombin 338 .+-. 8 32 .+-. 4 334 .+-. 15 321 .+-. 15 (nM) (nM) ETP
(nM) 567 .+-. 61 no ETP 830 .+-. 131 756 .+-. 38 ETP (nM) 973 .+-.
18 694 .+-. 67 1027 .+-. 19 1012 .+-. 33
TABLE-US-00005 TABLE 4 Effect of Edoxaban on TF-initiated TG
parameters for r-hFX and c-FX-C. Values represent experimental TG
values obtained in the presence of increasing concentrations of
Edoxaban. Edoxaban (nM) control 50 100 200 400 600 1000 2000 r-hFX
Lagtime(s) 115 247 297 397 538 679 874 1180 ETP remaining 100.%
99.3 87.1 no ETP no ETP no ETP no ETP no ETP Peak height % 100.%
41.2 30.8 23.1 15.9 13.0 10.1 7.1 Time to peak(s) 265 618 756 1290
1890 1932 2472 2562 c-FX -C Lagtime(s) 188 161 161 172 182 197 212
232 ETP remaining 100.% 87.9 92.5 88.3 92.7 96.8 92.7 82.0 Peak
height % 100.% 109.3 112.3 101.0 94.6 88.7 77.5 65.3 Time to
peak(s) 433 382 388 418 448 483 538 578
Sequence CWU 1
1
371488PRTHomo sapiens 1Met Gly Arg Pro Leu His Leu Val Leu Leu Ser
Ala Ser Leu Ala Gly1 5 10 15Leu Leu Leu Leu Gly Glu Ser Leu Phe Ile
Arg Arg Glu Gln Ala Asn 20 25 30Asn Ile Leu Ala Arg Val Thr Arg Ala
Asn Ser Phe Leu Glu Glu Met 35 40 45Lys Lys Gly His Leu Glu Arg Glu
Cys Met Glu Glu Thr Cys Ser Tyr 50 55 60Glu Glu Ala Arg Glu Val Phe
Glu Asp Ser Asp Lys Thr Asn Glu Phe65 70 75 80Trp Asn Lys Tyr Lys
Asp Gly Asp Gln Cys Glu Thr Ser Pro Cys Gln 85 90 95Asn Gln Gly Lys
Cys Lys Asp Gly Leu Gly Glu Tyr Thr Cys Thr Cys 100 105 110Leu Glu
Gly Phe Glu Gly Lys Asn Cys Glu Leu Phe Thr Arg Lys Leu 115 120
125Cys Ser Leu Asp Asn Gly Asp Cys Asp Gln Phe Cys His Glu Glu Gln
130 135 140Asn Ser Val Val Cys Ser Cys Ala Arg Gly Tyr Thr Leu Ala
Asp Asn145 150 155 160Gly Lys Ala Cys Ile Pro Thr Gly Pro Tyr Pro
Cys Gly Lys Gln Thr 165 170 175Leu Glu Arg Arg Lys Arg Ser Val Ala
Gln Ala Thr Ser Ser Ser Gly 180 185 190Glu Ala Pro Asp Ser Ile Thr
Trp Lys Pro Tyr Asp Ala Ala Asp Leu 195 200 205Asp Pro Thr Glu Asn
Pro Phe Asp Leu Leu Asp Phe Asn Gln Thr Gln 210 215 220Pro Glu Arg
Gly Asp Asn Asn Leu Thr Arg Ile Val Gly Gly Gln Glu225 230 235
240Cys Lys Asp Gly Glu Cys Pro Trp Gln Ala Leu Leu Ile Asn Glu Glu
245 250 255Asn Glu Gly Phe Cys Gly Gly Thr Ile Leu Ser Glu Phe Tyr
Ile Leu 260 265 270Thr Ala Ala His Cys Leu Tyr Gln Ala Lys Arg Phe
Lys Val Arg Val 275 280 285Gly Asp Arg Asn Thr Glu Gln Glu Glu Gly
Gly Glu Ala Val His Glu 290 295 300Val Glu Val Val Ile Lys His Asn
Arg Phe Thr Lys Glu Thr Tyr Asp305 310 315 320Phe Asp Ile Ala Val
Leu Arg Leu Lys Thr Pro Ile Thr Phe Arg Met 325 330 335Asn Val Ala
Pro Ala Cys Leu Pro Glu Arg Asp Trp Ala Glu Ser Thr 340 345 350Leu
Met Thr Gln Lys Thr Gly Ile Val Ser Gly Phe Gly Arg Thr His 355 360
365Glu Lys Gly Arg Gln Ser Thr Arg Leu Lys Met Leu Glu Val Pro Tyr
370 375 380Val Asp Arg Asn Ser Cys Lys Leu Ser Ser Ser Phe Ile Ile
Thr Gln385 390 395 400Asn Met Phe Cys Ala Gly Tyr Asp Thr Lys Gln
Glu Asp Ala Cys Gln 405 410 415Gly Asp Ser Gly Gly Pro His Val Thr
Arg Phe Lys Asp Thr Tyr Phe 420 425 430Val Thr Gly Ile Val Ser Trp
Gly Glu Gly Cys Ala Arg Lys Gly Lys 435 440 445Tyr Gly Ile Tyr Thr
Lys Val Thr Ala Phe Leu Lys Trp Ile Asp Arg 450 455 460Ser Met Lys
Thr Arg Gly Leu Pro Lys Ala Lys Ser His Ala Pro Glu465 470 475
480Val Ile Thr Ser Ser Pro Leu Lys 4852139PRTHomo sapiens 2Ala Asn
Ser Phe Leu Glu Glu Met Lys Lys Gly His Leu Glu Arg Glu1 5 10 15Cys
Met Glu Glu Thr Cys Ser Tyr Glu Glu Ala Arg Glu Val Phe Glu 20 25
30Asp Ser Asp Lys Thr Asn Glu Phe Trp Asn Lys Tyr Lys Asp Gly Asp
35 40 45Gln Cys Glu Thr Ser Pro Cys Gln Asn Gln Gly Lys Cys Lys Asp
Gly 50 55 60Leu Gly Glu Tyr Thr Cys Thr Cys Leu Glu Gly Phe Glu Gly
Lys Asn65 70 75 80Cys Glu Leu Phe Thr Arg Lys Leu Cys Ser Leu Asp
Asn Gly Asp Cys 85 90 95Asp Gln Phe Cys His Glu Glu Gln Asn Ser Val
Val Cys Ser Cys Ala 100 105 110Arg Gly Tyr Thr Leu Ala Asp Asn Gly
Lys Ala Cys Ile Pro Thr Gly 115 120 125Pro Tyr Pro Cys Gly Lys Gln
Thr Leu Glu Arg 130 1353254PRTHomo sapiens 3Ile Val Gly Gly Gln Glu
Cys Lys Asp Gly Glu Cys Pro Trp Gln Ala1 5 10 15Leu Leu Ile Asn Glu
Glu Asn Glu Gly Phe Cys Gly Gly Thr Ile Leu 20 25 30Ser Glu Phe Tyr
Ile Leu Thr Ala Ala His Cys Leu Tyr Gln Ala Lys 35 40 45Arg Phe Lys
Val Arg Val Gly Asp Arg Asn Thr Glu Gln Glu Glu Gly 50 55 60Gly Glu
Ala Val His Glu Val Glu Val Val Ile Lys His Asn Arg Phe65 70 75
80Thr Lys Glu Thr Tyr Asp Phe Asp Ile Ala Val Leu Arg Leu Lys Thr
85 90 95Pro Ile Thr Phe Arg Met Asn Val Ala Pro Ala Cys Leu Pro Glu
Arg 100 105 110Asp Trp Ala Glu Ser Thr Leu Met Thr Gln Lys Thr Gly
Ile Val Ser 115 120 125Gly Phe Gly Arg Thr His Glu Lys Gly Arg Gln
Ser Thr Arg Leu Lys 130 135 140Met Leu Glu Val Pro Tyr Val Asp Arg
Asn Ser Cys Lys Leu Ser Ser145 150 155 160Ser Phe Ile Ile Thr Gln
Asn Met Phe Cys Ala Gly Tyr Asp Thr Lys 165 170 175Gln Glu Asp Ala
Cys Gln Gly Asp Ser Gly Gly Pro His Val Thr Arg 180 185 190Phe Lys
Asp Thr Tyr Phe Val Thr Gly Ile Val Ser Trp Gly Glu Gly 195 200
205Cys Ala Arg Lys Gly Lys Tyr Gly Ile Tyr Thr Lys Val Thr Ala Phe
210 215 220Leu Lys Trp Ile Asp Arg Ser Met Lys Thr Arg Gly Leu Pro
Lys Ala225 230 235 240Lys Ser His Ala Pro Glu Val Ile Thr Ser Ser
Pro Leu Lys 245 250420PRTArtificial Sequencefragment of altered FX
4Thr Lys Phe Val Pro Pro Asn Tyr Tyr Tyr Val His Gln Asn Phe Asp1 5
10 15Arg Val Ala Tyr 20521PRTArtificial Sequencefragment of altered
FX 5Lys Lys Phe Val Pro Pro Lys Lys Ser Gln Glu Phe Tyr Glu Lys
Phe1 5 10 15Asp Leu Val Ser Tyr 2061473DNAHomo sapiens 6atggcgcacg
tccgaggctt gcagctgcct ggctgcctgg ccctggctgc cctgtgtagc 60cttgtgcaca
gccagcatgt gttcctggct cctcagcaag cacggtcgct gctccagcgg
120gtccggcgag ccaattcctt tcttgaagag atgaagaaag gacacctcga
aagagagtgc 180atggaagaga cctgctcata cgaagaggcc cgcgaggtct
ttgaggacag cgacaagacg 240aatgaattct ggaataaata caaagatggc
gaccagtgtg agaccagtcc ttgccagaac 300cagggcaaat gtaaagacgg
cctcggggaa tacacctgca cctgtttaga aggattcgaa 360ggcaaaaact
gtgaattatt cacacggaag ctctgcagcc tggacaacgg ggactgtgac
420cagttctgcc acgaggaaca gaactctgtg gtgtgctcct gcgcccgcgg
gtacaccctg 480gctgacaacg gcaaggcctg cattcccaca gggccctacc
cctgtgggaa acagaccctg 540gaacgcagga agaggtcagt ggcccaggcc
accagcagca gcggggaggc ccctgacagc 600atcacatgga agccatatga
tgcagccgac ctggacccca ccgagaaccc cttcgacctg 660cttgacttca
accagacgca gcctgagagg ggcgacaaca acctcacgcg tatcgtggga
720ggccaggaat gcaaggacgg ggagtgtccc tggcaggccc tgctcatcaa
tgaggaaaac 780gagggtttct gtggtggaac tattctgagc gagttctaca
tcctaacggc agcccactgt 840ctctaccaag ccaagagatt caaggtgagg
gtaggtgacc ggaacacgga gcaggaggag 900ggcggtgagg cggtgcacga
ggtggaggtg gtcatcaagc acaaccggtt cacaaaggag 960acctatgact
tcgacatcgc cgtgctccgg ctcaagaccc ccatcacctt ccgcatgaac
1020gtggcgcctg cctgcctccc cgagcgtgac tgggccgagt ccacgctgat
gacgcagaag 1080acggggattg tgagcggctt cgggcgcacc cacgagaagg
gccggcagtc caccaggctc 1140aagatgctgg aggtgcccta cgtggaccgc
aacagctgca agctgtccag cagcttcatc 1200atcacccaga acatgttctg
tgccggctac gacaccaagc aggaggatgc ctgccagggg 1260gacagcgggg
gcccgcacgt cacccgcttc aaggacacct acttcgtgac aggcatcgtc
1320agctggggag agggctgtgc ccgtaagggg aagtacggga tctacaccaa
ggtcaccgcc 1380ttcctcaagt ggatcgacag gtccatgaaa accaggggct
tgcccaaggc caagagccat 1440gccccggagg tcataacgtc ctctccattg aaa
147371509DNAArtificial Sequenceof modified human FX - type A
7atggcgcacg tccgaggctt gcagctgcct ggctgcctgg ccctggctgc cctgtgtagc
60cttgtgcaca gccagcatgt gttcctggct cctcagcaag cacggtcgct gctccagcgg
120gtccggcgag ccaattcctt tcttgaagag atgaagaaag gacacctcga
aagagagtgc 180atggaagaga cctgctcata cgaagaggcc cgcgaggtct
ttgaggacag cgacaagacg 240aatgaattct ggaataaata caaagatggc
gaccagtgtg agaccagtcc ttgccagaac 300cagggcaaat gtaaagacgg
cctcggggaa tacacctgca cctgtttaga aggattcgaa 360ggcaaaaact
gtgaattatt cacacggaag ctctgcagcc tggacaacgg ggactgtgac
420cagttctgcc acgaggaaca gaactctgtg gtgtgctcct gcgcccgcgg
gtacaccctg 480gctgacaacg gcaaggcctg cattcccaca gggccctacc
cctgtgggaa acagaccctg 540gaacgcagga agaggtcagt ggcccaggcc
accagcagca gcggggaggc ccctgacagc 600atcacatgga agccatatga
tgcagccgac ctggacccca ccgagaaccc cttcgacctg 660cttgacttca
accagacgca gcctgagagg ggcgacaaca acctcacgcg tatcgtggga
720ggccaggaat gcaaggacgg ggagtgtccc tggcaggccc tgctcatcaa
tgaggaaaac 780gagggtttct gtggtggaac tattctgagc gagttctaca
tcctaacggc agcccactgt 840ctctaccaag ccaagagatt caaggtgagg
gtaggtgacc ggaacacgga gcaggaggag 900ggcggtgagg cggtgcacga
ggtggaggtg gtcatcaagc acaccaagtt cgtgccccct 960aactactatt
acgtccacca gaattttgac cgggtggcct atgacttcga catcgccgtg
1020ctccggctca agacccccat caccttccgc atgaacgtgg cgcctgcctg
cctccccgag 1080cgtgactggg ccgagtccac gctgatgacg cagaagacgg
ggattgtgag cggcttcggg 1140cgcacccacg agaagggccg gcagtccacc
aggctcaaga tgctggaggt gccctacgtg 1200gaccgcaaca gctgcaagct
gtccagcagc ttcatcatca cccagaacat gttctgtgcc 1260ggctacgaca
ccaagcagga ggatgcctgc cagggggaca gcgggggccc gcacgtcacc
1320cgcttcaagg acacctactt cgtgacaggc atcgtcagct ggggagaggg
ctgtgcccgt 1380aaggggaagt acgggatcta caccaaggtc accgccttcc
tcaagtggat cgacaggtcc 1440atgaaaacca ggggcttgcc caaggccaag
agccatgccc cggaggtcat aacgtcctct 1500ccattgaaa
150981512DNAArtificial Sequenceof modified human FX - type B
8atggcgcacg tccgaggctt gcagctgcct ggctgcctgg ccctggctgc cctgtgtagc
60cttgtgcaca gccagcatgt gttcctggct cctcagcaag cacggtcgct gctccagcgg
120gtccggcgag ccaattcctt tcttgaagag atgaagaaag gacacctcga
aagagagtgc 180atggaagaga cctgctcata cgaagaggcc cgcgaggtct
ttgaggacag cgacaagacg 240aatgaattct ggaataaata caaagatggc
gaccagtgtg agaccagtcc ttgccagaac 300cagggcaaat gtaaagacgg
cctcggggaa tacacctgca cctgtttaga aggattcgaa 360ggcaaaaact
gtgaattatt cacacggaag ctctgcagcc tggacaacgg ggactgtgac
420cagttctgcc acgaggaaca gaactctgtg gtgtgctcct gcgcccgcgg
gtacaccctg 480gctgacaacg gcaaggcctg cattcccaca gggccctacc
cctgtgggaa acagaccctg 540gaacgcagga agaggtcagt ggcccaggcc
accagcagca gcggggaggc ccctgacagc 600atcacatgga agccatatga
tgcagccgac ctggacccca ccgagaaccc cttcgacctg 660cttgacttca
accagacgca gcctgagagg ggcgacaaca acctcacgcg tatcgtggga
720ggccaggaat gcaaggacgg ggagtgtccc tggcaggccc tgctcatcaa
tgaggaaaac 780gagggtttct gtggtggaac tattctgagc gagttctaca
tcctaacggc agcccactgt 840ctctaccaag ccaagagatt caaggtgagg
gtaggtgacc ggaacacgga gcaggaggag 900ggcggtgagg cggtgcacga
ggtggaggtg gtcatcaagc acaagaaatt cgtgccccct 960aagaaaagcc
aggagttcta cgaaaagttt gacctggtct cctatgactt cgacatcgcc
1020gtgctccggc tcaagacccc catcaccttc cgcatgaacg tggcgcctgc
ctgcctcccc 1080gagcgtgact gggccgagtc cacgctgatg acgcagaaga
cggggattgt gagcggcttc 1140gggcgcaccc acgagaaggg ccggcagtcc
accaggctca agatgctgga ggtgccctac 1200gtggaccgca acagctgcaa
gctgtccagc agcttcatca tcacccagaa catgttctgt 1260gccggctacg
acaccaagca ggaggatgcc tgccaggggg acagcggggg cccgcacgtc
1320acccgcttca aggacaccta cttcgtgaca ggcatcgtca gctggggaga
gggctgtgcc 1380cgtaagggga agtacgggat ctacaccaag gtcaccgcct
tcctcaagtg gatcgacagg 1440tccatgaaaa ccaggggctt gcccaaggcc
aagagccatg ccccggaggt cataacgtcc 1500tctccattga aa
1512921PRTArtificial Sequencechimeric FX type A 9Lys Lys Phe Val
Pro Pro Lys Lys Ser Gln Glu Phe Tyr Glu Lys Phe1 5 10 15Asp Leu Ala
Ala Tyr 201020PRTArtificial Sequencechimeric FX type B 10Lys Lys
Phe Val Pro Pro Asn Tyr Tyr Tyr Val His Gln Asn Phe Asp1 5 10 15Leu
Ala Ala Tyr 201117PRTArtificial Sequencechimeric FX type C 11Lys
Lys Phe Val Pro Pro Gln Lys Ala Tyr Lys Phe Asp Leu Ala Ala1 5 10
15Tyr126PRTHomo sapiens 12His Asn Arg Phe Thr Lys1 5136PRTHomo
sapiens 13Glu Thr Tyr Asp Phe Asp1 5146PRTMus musculus 14His Asn
Lys Phe Gln Arg1 5156PRTMus musculus 15Asp Thr Tyr Asp Tyr Asp1
5166PRTGallus gallus 16His Ser Lys Tyr Ile Ala1 5176PRTGallus
gallus 17Glu Thr Tyr Asp Tyr Asp1 5186PRTAnolis carolinensis 18His
Gln Lys Phe Val Leu1 5196PRTAnolis carolinensis 19Ala Thr Tyr Asp
Tyr Asp1 5206PRTSilurana tropicalis 20His Pro Arg Phe Val Lys1
5216PRTSilurana tropicalis 21Ser Thr Tyr Asp Tyr Asp1 5226PRTDanio
rerio 22His Lys Asn Tyr Gln Pro1 5236PRTDanio rerio 23Asp Thr Tyr
His Asn Asp1 5246PRTTakifugu rubripes 24His Asn Arg Phe Thr Lys1
5256PRTTakifugu rubripes 25Asn Thr Tyr His Asn Asp1
5266PRTPseudonaja textilis 26His Gln Lys Phe Val Pro1
52725PRTPseudonaja textilis 27His Lys Lys Phe Val Pro Pro Lys Lys
Ser Gln Glu Phe Tyr Glu Lys1 5 10 15Phe Asp Leu Val Ser Tyr Asp Tyr
Asp 20 252824PRTNotechis scutatus 28His Thr Lys Phe Val Pro Pro Asn
Tyr Tyr Tyr Val His Gln Asn Phe1 5 10 15Asp Arg Val Ala Tyr Asp Tyr
Asp 2029481PRTMus musculus 29Met Gly Ser Pro Val Gln Leu Ser Leu
Leu Cys Val Val Leu Ala Ser1 5 10 15Leu Leu Leu Pro Gly Lys Gly Val
Phe Ile Asn Arg Glu Arg Ala Asn 20 25 30Asn Val Leu Ala Arg Thr Arg
Arg Ala Asn Ser Phe Phe Glu Glu Phe 35 40 45Lys Lys Gly Asn Leu Glu
Arg Glu Cys Met Glu Glu Ile Cys Ser Tyr 50 55 60Glu Glu Val Arg Glu
Ile Phe Glu Asp Asp Glu Lys Thr Lys Glu Tyr65 70 75 80Trp Thr Lys
Tyr Lys Asp Gly Asp Gln Cys Glu Ser Ser Pro Cys Gln 85 90 95Asn Gln
Gly Ala Cys Arg Asp Gly Ile Gly Gly Tyr Thr Cys Thr Cys 100 105
110Ser Glu Gly Phe Glu Gly Lys Asn Cys Glu Leu Phe Val Arg Lys Leu
115 120 125Cys Arg Leu Asp Asn Gly Asp Cys Asp Gln Phe Cys Arg Glu
Glu Gln 130 135 140Asn Ser Val Val Cys Ser Cys Ala Ser Gly Tyr Phe
Leu Gly Asn Asp145 150 155 160Gly Lys Ser Cys Ile Ser Thr Ala Pro
Phe Pro Cys Gly Lys Ile Thr 165 170 175Thr Gly Arg Arg Lys Arg Ser
Val Ala Leu Asn Thr Ser Asp Ser Glu 180 185 190Leu Asp Leu Glu Asp
Ala Leu Leu Asp Glu Asp Phe Leu Ser Pro Thr 195 200 205Glu Asn Pro
Ile Glu Leu Leu Asn Leu Asn Glu Thr Gln Pro Glu Arg 210 215 220Ser
Ser Asp Asp Leu Val Arg Ile Val Gly Gly Arg Glu Cys Lys Asp225 230
235 240Gly Glu Cys Pro Trp Gln Ala Leu Leu Ile Asn Glu Asp Asn Glu
Gly 245 250 255Phe Cys Gly Gly Thr Ile Leu Asn Glu Phe Tyr Ile Leu
Thr Ala Ala 260 265 270His Cys Leu His Gln Ala Arg Arg Phe Lys Val
Arg Val Gly Asp Arg 275 280 285Asn Thr Glu Lys Glu Glu Gly Asn Glu
Met Val His Glu Val Asp Val 290 295 300Val Ile Lys His Asn Lys Phe
Gln Arg Asp Thr Tyr Asp Tyr Asp Ile305 310 315 320Ala Val Leu Arg
Leu Lys Thr Pro Ile Thr Phe Arg Met Asn Val Ala 325 330 335Pro Ala
Cys Leu Pro Gln Lys Asp Trp Ala Glu Ser Thr Leu Met Thr 340 345
350Gln Lys Thr Gly Ile Val Ser Gly Phe Gly Arg Thr His Glu Lys Gly
355 360 365Arg Gln Ser Asn Ile Leu Lys Met Leu Glu Val Pro Tyr Val
Asp Arg 370 375 380Asn Thr Cys Lys Leu Ser Thr Ser Phe Ser Ile Thr
Gln Asn Met Phe385 390 395 400Cys Ala Gly Tyr Glu Ala Lys Leu Glu
Asp Ala Cys Gln Gly Asp Ser 405 410 415Gly Gly Pro His Val Thr Arg
Phe Lys Asn Thr Tyr Tyr Val Thr Gly 420 425 430Ile Val Ser Trp Gly
Glu Gly Cys Ala Arg Lys Gly Lys Tyr Gly Ile 435 440 445Tyr Thr Lys
Val Thr Thr Phe Leu Lys Trp Ile Asp Arg Ser Met Lys 450 455 460Ala
Arg Val Gly Pro Thr Ala Glu Thr Pro Arg Thr Ala Gly Pro Pro465 470
475 480Asn30464PRTSilurana tropicalis 30Met Ala Gly Gln Thr Cys Leu
Ile Ile
Leu Ile Ala Leu Pro Ala Val1 5 10 15Leu Leu Gln Gln Ser Pro Asn Val
Phe Leu Lys His Glu Asn Ala His 20 25 30Asn Ile Leu Arg Ala Lys Arg
Ala Asn Ser Ala Phe Glu Glu Phe Lys 35 40 45Lys Gly Asn Leu Glu Arg
Glu Cys Tyr Glu Glu Arg Cys Ser Leu Glu 50 55 60Glu Ala Arg Glu Val
Phe Glu Asn Glu Glu Gln Thr Arg Glu Phe Trp65 70 75 80Ser Lys Tyr
Phe Asp Gly Asp Gln Cys Gln Ser Asn Pro Cys Gln Tyr 85 90 95Gly Gly
Ser Cys Asn Asp Gly Ile Asn Glu Tyr Thr Cys Leu Cys Asn 100 105
110Ala Gly Phe Glu Gly Lys Asn Cys Glu Thr Val Lys Leu Gln Leu Cys
115 120 125Ser Leu Asn Asn Gly Glu Cys Asp Gln Tyr Cys Lys Ala Val
Asp Arg 130 135 140Asp Val Val Cys Ser Cys Thr Asn Gly Tyr Ile Leu
Gly Glu Asn Gly145 150 155 160Lys Ser Cys Leu Pro Thr Glu Lys Tyr
Ser Cys Gly Arg Arg His Met 165 170 175Lys Arg Glu Arg Arg Glu Thr
Lys Leu His Glu Asn Asp Lys Lys Asn 180 185 190His Thr Asp Ser Gln
Asn Glu Val Lys Met Asn Gln Thr Gly Thr Leu 195 200 205Pro Glu Arg
Asn Val Thr Gly Ile Asn Ile Leu Asn Pro Asn Asp Pro 210 215 220Asn
Val Arg Ile Val Gly Gly Arg Glu Cys Ser Gln Gly Glu Cys Pro225 230
235 240Trp Gln Ala Leu Leu Val Ser Asp Glu Asp Glu Gly Phe Cys Gly
Gly 245 250 255Thr Ile Leu Ser Arg Glu Phe Ile Leu Thr Ala Ala His
Cys Met Asn 260 265 270Gln Thr Lys Tyr Phe Lys Val Val Val Gly Glu
Leu Asn Thr Lys Ile 275 280 285Ser Glu Gly Thr Glu Ser Ile His Lys
Val Glu Lys Ile Ile Met His 290 295 300Pro Arg Phe Val Lys Ser Thr
Tyr Asp Tyr Asp Ile Ala Val Ile Lys305 310 315 320Leu Lys Glu Ala
Ile Asn Phe Thr Glu Asn Ile Ile Pro Ala Cys Ile 325 330 335Pro Asp
Pro Glu Phe Ala Asp Gln Val Leu Met Asn Glu Pro Asp Ala 340 345
350Met Val Ser Gly Phe Gly Arg Ile His Glu Arg Gly Arg Gln Ala Ser
355 360 365Thr Leu Gln Met Leu Gln Val Pro Tyr Ile Lys Arg His Ser
Cys Lys 370 375 380Glu Ser Ser Thr Phe Ala Ile Thr Glu Asn Met Phe
Cys Ala Gly Phe385 390 395 400Asp Thr Glu Val Lys Asp Ala Cys Gln
Gly Asp Ser Gly Gly Pro His 405 410 415Val Thr Pro Phe Lys Gly Thr
Tyr Phe Val Thr Gly Ile Val Ser Trp 420 425 430Gly Glu Gly Cys Ala
Arg Lys Gly Lys Phe Gly Val Tyr Thr Lys Val 435 440 445Ser Lys Leu
His Arg Trp Leu Lys Gly Val Leu Lys Lys Asn Gln Val 450 455
46031474PRTDanio rerio 31Met Ser Trp Val Phe Trp Asn Phe Ile Ser
Leu Phe Val Thr His Ser1 5 10 15Val Cys Ala Glu Val Phe Leu Asn Thr
Arg Asp Ala Asn Gln Val Leu 20 25 30Ile Arg Gln Arg Arg Ala Asn Ser
Leu Phe Glu Glu Met Glu Lys Gly 35 40 45Asn Met Glu Arg Glu Cys Ile
Glu Glu Arg Cys Asn Tyr Glu Glu Ala 50 55 60Arg Glu Ile Phe Glu Asp
Val Lys Lys Thr Asp Glu Phe Trp His Lys65 70 75 80Tyr Val Asp Gly
Lys Asn Ala Cys Leu Ser His Pro Cys Val Asn Gly 85 90 95Gly Gln Cys
Lys Asp Ala Ile Gly Pro Tyr Thr Cys Phe Cys Gln Gln 100 105 110Gly
Phe Lys Gly Tyr Asn Cys Glu Ile Val Ile Pro Glu Leu Cys Glu 115 120
125Asn Glu Asn Gly Gly Cys Asp His Phe Cys Glu Val Met Glu Lys Asn
130 135 140Val Val Cys Ser Cys Ala Asn Gly Tyr Glu Leu Ala Pro Asn
Gly Lys145 150 155 160Ser Cys Gln Ser Gln Asp Pro Phe Lys Cys Gly
Val Ile Tyr Pro Lys 165 170 175Lys Thr Arg Ser Ile Phe Phe His Thr
Pro Asn Ile Thr Glu Ser Glu 180 185 190Asn Glu Glu Glu Thr Glu Leu
Glu Ala Thr Ile Glu Pro Val Tyr Asn 195 200 205His Ser Asn Pro Leu
Asn Asn Gln Thr Asp Ser Met Phe Gly Leu His 210 215 220Glu Leu Glu
Ile Ile Gln Glu Glu Pro Ile Leu Pro Val Val Ser Thr225 230 235
240Ala Gly Asp Gly Arg Ile Val Asn Gly Val Glu Cys Pro Pro Gly Asp
245 250 255Cys Pro Trp Gln Ala Leu Leu Ile Asn Glu Asn Asn Met Gly
Phe Cys 260 265 270Gly Gly Thr Ile Leu Thr Glu His Phe Ile Leu Ser
Ala Ala His Cys 275 280 285Met Asn Glu Ser Leu Ser Ile Arg Val Val
Val Gly Glu Tyr Asp Thr 290 295 300Leu Val Pro Glu Gly Arg Glu Ala
Thr His Asp Val Asp Glu Ile Leu305 310 315 320Ile His Lys Asn Tyr
Gln Pro Asp Thr Tyr His Asn Asp Ile Ala Leu 325 330 335Ile Lys Leu
Ser Lys Pro Ile Lys Phe Thr Lys Tyr Ile Ile Pro Ala 340 345 350Cys
Leu Pro Glu Met Lys Phe Ala Glu Arg Val Leu Met Gln Gln Asp 355 360
365Asp Gly Leu Val Ser Gly Phe Gly Arg Val Arg Glu Gly Gly Leu Ser
370 375 380Ser Thr Ile Leu Gln Lys Leu Thr Val Pro Tyr Val Asn Arg
Ala Lys385 390 395 400Cys Ile Glu Ser Ser Asn Phe Lys Ile Ser Gly
Arg Met Phe Cys Ala 405 410 415Gly Tyr Asp Gln Glu Glu Lys Asp Ala
Cys Gln Gly Asp Ser Gly Gly 420 425 430Pro His Val Thr Arg Phe Lys
Asn Thr Trp Phe Ile Thr Gly Val Val 435 440 445Lys Leu Gly Arg Arg
Val Arg Ala Gln Gly Glu Ile Arg Arg Leu His 450 455 460Thr Gly Leu
Gln Ile His His Val Asp Gln465 47032475PRTTakifugu rubripes 32Met
Phe Arg Leu Phe Phe Ile Ala Phe Leu Asp Lys Thr Gly Ala Ser1 5 10
15Gln Leu Leu Ser Arg Gln Arg Arg Ala Asn Ser Leu Phe Glu Glu Val
20 25 30Lys Gln Gly Asn Met Glu Arg Glu Cys Asn Glu Glu His Cys Ser
Lys 35 40 45Glu Glu Ala Arg Glu Ile Phe Glu Asp Asp Asp Gln Thr Asn
Glu Phe 50 55 60Trp Ala Ile Tyr Tyr Asp Gly Asp Ala Cys Lys Ser Thr
Pro Cys Val65 70 75 80Asn Lys Gly Arg Cys Lys Asp Gly Ile Gly Ser
Tyr Thr Cys Phe Cys 85 90 95Leu Ser Gly Tyr Gln Gly Phe Asn Cys Glu
Ile Val Ile Pro Gln Leu 100 105 110Cys Glu Asn Glu Asn Gly Gly Cys
Glu His Phe Cys Lys Val Val Arg 115 120 125Gly Asn Val Arg Cys Ser
Cys Ala Asp Gly Tyr Glu Leu Gly Pro Asp 130 135 140Asp Lys Ser Cys
Gln Ser Asn Glu Thr Phe Arg Cys Gly Gly Ile Ile145 150 155 160Thr
Glu Asn Val Arg Thr Ile Leu Arg Tyr Arg Pro Asn Thr Asn Thr 165 170
175Asn Gly Thr Lys Ser Asp Asn Ser Ser Ser Thr Asn Ser Thr Glu Gln
180 185 190Glu Asp Glu Glu Phe Ser Ser Gly Thr Ser Gln Arg Lys Ala
His Ala 195 200 205Ala Ser Asp His Glu Met Ser Thr Met Thr Arg Ile
Val Asn Gly Glu 210 215 220Asp Cys Pro Pro Gly Glu Cys Pro Trp Gln
Ala Val Leu Leu Asn Glu225 230 235 240Glu His His Trp Phe Cys Gly
Gly Thr Ile Leu Asn Pro Tyr Ile Ile 245 250 255Leu Thr Ala Ala His
Cys Met Asn Glu Thr Arg Tyr Phe Tyr Ile Arg 260 265 270Leu Gly Glu
Ser Asp Met Leu Glu Asn Glu Gly Thr Glu Ala Met Tyr 275 280 285Glu
Val Glu Thr Ile Leu Ala His Tyr Asn Tyr Lys Pro Asn Thr Tyr 290 295
300His Asn Asp Ile Ala Leu Ile Lys Leu Thr Lys Pro Ile Lys Tyr
Ser305 310 315 320Arg Phe Ile Leu Pro Ala Cys Ile Pro Glu Gln Glu
Phe Ala Glu Ser 325 330 335Val Leu Met Gln Gln Ser Asp Gly Met Ile
Ser Gly Phe Gly Arg Leu 340 345 350Gly Gly Asn Arg Gln Thr Ser Pro
Ile Leu Lys Arg Leu Thr Ile Pro 355 360 365Tyr Val Glu Arg Arg Thr
Cys Met Glu Ser Thr Ser Leu Arg Ile Ser 370 375 380Ala Arg Met Phe
Cys Ala Gly Tyr Asp Glu Ile Ala Lys Asp Ala Cys385 390 395 400Gln
Gly Asp Ser Gly Gly Pro His Val Thr Arg Tyr Arg Ser Thr Tyr 405 410
415Phe Ile Thr Gly Ile Val Ser Trp Gly Glu Gly Cys Ala Gln Lys Gly
420 425 430Lys Tyr Gly Val Tyr Thr Gln Val Ser Lys Tyr Ile Arg Trp
Ile Arg 435 440 445Asp Gly Ile Asn Thr Leu Ile Pro Lys Gly Gln Ser
Thr Arg Leu Lys 450 455 460Arg His Tyr Gly Pro Ile Arg Arg Ile Val
Gly465 470 47533483PRTPseudonaja textilis 33Met Ala Pro Gln Leu Leu
Leu Cys Leu Ile Leu Thr Phe Leu Trp Ser1 5 10 15Leu Pro Glu Ala Glu
Ser Asn Val Phe Leu Lys Ser Lys Val Ala Asn 20 25 30Arg Phe Leu Gln
Arg Thr Lys Arg Ala Asn Ser Leu Phe Glu Glu Phe 35 40 45Lys Ser Gly
Asn Ile Glu Arg Glu Cys Ile Glu Glu Arg Cys Ser Lys 50 55 60Glu Glu
Ala Arg Glu Ala Phe Glu Asp Asp Glu Lys Thr Glu Thr Phe65 70 75
80Trp Asn Val Tyr Val Asp Gly Asp Gln Cys Ser Ser Asn Pro Cys His
85 90 95Tyr Gly Gly Thr Cys Lys Asp Gly Ile Gly Ser Tyr Thr Cys Thr
Cys 100 105 110Leu Ser Gly Tyr Glu Gly Lys Asn Cys Glu Tyr Val Leu
Tyr Lys Ser 115 120 125Cys Arg Val Asp Asn Gly Asp Cys Trp His Phe
Cys Lys Pro Val Gln 130 135 140Asn Gly Ile Gln Cys Ser Cys Ala Glu
Ser Tyr Leu Leu Gly Glu Asp145 150 155 160Gly His Ser Cys Val Ala
Gly Gly Asp Phe Ser Cys Gly Arg Asn Ile 165 170 175Lys Thr Arg Asn
Lys Arg Glu Ala Asn Leu Pro Asp Phe Gln Thr Asp 180 185 190Phe Ser
Asp Asp Tyr Asp Glu Ile Asp Glu Asn Asn Phe Val Glu Thr 195 200
205Pro Thr Asn Phe Ser Gly Leu Val Leu Thr Val Gln Ser Gln Asn Ala
210 215 220Thr Leu Leu Lys Lys Ser Asp Asn Pro Ser Pro Asp Ile Arg
Val Val225 230 235 240Asn Gly Thr Asp Cys Lys Leu Gly Glu Cys Pro
Trp Gln Ala Leu Leu 245 250 255Leu Asn Asp Glu Gly Asp Gly Phe Cys
Gly Gly Thr Ile Leu Ser Pro 260 265 270Ile Tyr Val Leu Thr Ala Ala
His Cys Ile Asn Gln Thr Lys Tyr Ile 275 280 285Thr Val Val Val Gly
Glu Ile Asp Ile Ser Ser Lys Lys Thr Gly Arg 290 295 300Leu His Ser
Val Asp Lys Ile Tyr Val His Gln Lys Phe Val Pro Ala305 310 315
320Thr Tyr Asp Tyr Asp Ile Ala Ile Ile Gln Leu Lys Thr Pro Ile Gln
325 330 335Phe Ser Glu Asn Val Val Pro Ala Cys Leu Pro Thr Ala Asp
Phe Ala 340 345 350Asn Gln Val Leu Met Lys Gln Asn Phe Gly Ile Val
Ser Gly Phe Gly 355 360 365Arg Thr Arg Glu Arg Gly Lys Thr Ser Asn
Thr Leu Lys Val Val Thr 370 375 380Leu Pro Tyr Val Asp Arg His Thr
Cys Met Leu Ser Ser Asn Phe Pro385 390 395 400Ile Thr Gln Asn Met
Phe Cys Ala Gly Tyr Asp Thr Leu Pro Gln Asp 405 410 415Ala Cys Gln
Gly Asp Ser Gly Gly Pro His Ile Thr Ala Tyr Arg Asp 420 425 430Thr
His Phe Ile Thr Gly Ile Val Ser Trp Gly Glu Gly Cys Ala Gln 435 440
445Thr Gly Lys Tyr Gly Val Tyr Thr Lys Val Ser Lys Phe Ile Leu Trp
450 455 460Ile Lys Arg Ile Ile Arg Gln Lys Gln Pro Ser Thr Glu Ser
Ser Thr465 470 475 480Gly Arg Leu34463PRTPseudonaja textilis 34Met
Ala Pro Gln Leu Leu Leu Cys Leu Ile Leu Thr Phe Leu Trp Ser1 5 10
15Leu Pro Glu Ala Glu Ser Asn Val Phe Leu Lys Ser Lys Val Ala Asn
20 25 30Arg Phe Leu Gln Arg Thr Lys Arg Ala Asn Ser Leu Val Glu Glu
Phe 35 40 45Lys Ser Gly Asn Ile Glu Arg Glu Cys Ile Glu Glu Arg Cys
Ser Lys 50 55 60Glu Glu Ala Arg Glu Ala Phe Glu Asp Asp Glu Lys Thr
Glu Thr Phe65 70 75 80Trp Asn Val Tyr Val Asp Gly Asp Gln Cys Ser
Ser Asn Pro Cys His 85 90 95Tyr Arg Gly Ile Cys Lys Asp Gly Ile Gly
Ser Tyr Thr Cys Thr Cys 100 105 110Leu Ser Gly Tyr Glu Gly Lys Asn
Cys Glu Arg Val Leu Tyr Lys Ser 115 120 125Cys Arg Val Asp Asn Gly
Asn Cys Trp His Phe Cys Lys His Val Gln 130 135 140Asn Asp Ile Gln
Cys Ser Cys Ala Glu Gly Tyr Leu Leu Gly Glu Asp145 150 155 160Gly
His Ser Cys Val Ala Gly Gly Asn Phe Ser Cys Gly Arg Asn Ile 165 170
175Lys Thr Arg Asn Lys Arg Glu Ala Asn Leu Pro Asp Phe Val Gln Ser
180 185 190Gln Asn Ala Thr Leu Leu Lys Lys Ser Asp Asn Pro Ser Pro
Asp Ile 195 200 205Arg Ile Val Asn Gly Met Asp Cys Lys Leu Gly Glu
Cys Pro Trp Gln 210 215 220Ala Ala Leu Val Asp Glu Lys Glu Gly Val
Phe Cys Gly Gly Thr Ile225 230 235 240Leu Ser Pro Ile Tyr Val Leu
Thr Ala Ala His Cys Ile Asn Glu Thr 245 250 255Glu Thr Ile Ser Val
Val Val Gly Glu Ile Asp Lys Ser Arg Ile Glu 260 265 270Thr Gly Pro
Leu Leu Ser Val Asp Lys Ile Tyr Val His Lys Lys Phe 275 280 285Val
Pro Pro Gln Lys Ala Tyr Lys Phe Asp Leu Ala Ala Tyr Asp Tyr 290 295
300Asp Ile Ala Ile Ile Gln Met Lys Thr Pro Ile Gln Phe Ser Glu
Asn305 310 315 320Val Val Pro Ala Cys Leu Pro Thr Ala Asp Phe Ala
Asn Gln Val Leu 325 330 335Met Lys Gln Asp Phe Gly Ile Val Ser Gly
Phe Gly Arg Ile Phe Glu 340 345 350Lys Gly Pro Lys Ser Lys Thr Leu
Lys Val Leu Lys Val Pro Tyr Val 355 360 365Asp Arg His Thr Cys Met
Val Ser Ser Glu Thr Pro Ile Thr Pro Asn 370 375 380Met Phe Cys Ala
Gly Tyr Asp Thr Leu Pro Arg Asp Ala Cys Gln Gly385 390 395 400Asp
Ser Gly Gly Pro His Thr Thr Val Tyr Arg Asp Thr His Phe Ile 405 410
415Thr Gly Ile Val Ser Ser Gly Glu Gly Cys Ala Arg Asn Gly Lys Tyr
420 425 430Gly Ile Tyr Thr Lys Leu Ser Lys Phe Ile Pro Trp Ile Lys
Arg Ile 435 440 445Met Arg Gln Lys Leu Pro Ser Thr Glu Ser Ser Thr
Gly Arg Leu 450 455 46035449PRTPseudonaja textilis 35Met Ala Pro
Gln Leu Leu Leu Cys Leu Ile Leu Thr Phe Leu Trp Ser1 5 10 15Leu Pro
Glu Ala Glu Ser Asn Val Phe Leu Lys Ser Lys Val Ala Asn 20 25 30Arg
Phe Leu Gln Arg Thr Lys Arg Ala Asn Ser Leu Val Glu Glu Phe 35 40
45Lys Ser Gly Asn Ile Glu Arg Glu Cys Ile Glu Glu Arg Cys Ser Lys
50 55 60Glu Glu Ala Arg Glu Ala Phe Glu Asp Asp Glu Lys Thr Glu Thr
Phe65 70 75 80Trp Asn Val Tyr Val Asp Gly Asp Gln Cys Ser Ser Asn
Pro Cys His 85 90 95Tyr Arg Gly Ile Cys Lys Asp Gly Ile Gly Ser Tyr
Thr Cys Thr Cys 100 105
110Leu Ser Gly Tyr Glu Gly Lys Asn Cys Glu Arg Val Leu Tyr Lys Ser
115 120 125Cys Arg Val Asp Asn Gly Asn Cys Trp His Phe Cys Lys Ser
Val Gln 130 135 140Asn Asp Ile Gln Cys Ser Cys Ala Glu Gly Tyr Leu
Leu Gly Glu Asp145 150 155 160Gly His Ser Cys Val Ala Gly Gly Asn
Phe Ser Cys Gly Arg Asn Ile 165 170 175Lys Thr Arg Asn Lys Arg Glu
Ala Ser Leu Pro Asp Phe Val Gln Ser 180 185 190Gln Asn Ala Pro Leu
Leu Lys Ile Ser Asp Asn Pro Ser Pro Asp Ile 195 200 205Arg Ile Val
Asn Gly Met Asp Cys Lys Leu Gly Glu Cys Pro Trp Gln 210 215 220Ala
Ala Leu Val Asp Asp Lys Lys Gly Val Phe Cys Gly Gly Thr Ile225 230
235 240Leu Ser Pro Ile Tyr Val Leu Thr Ala Ala His Cys Ile Asn Glu
Thr 245 250 255Glu Thr Ile Ser Val Val Val Gly Glu Ile Asp Arg Ser
Arg Ala Glu 260 265 270Thr Gly Pro Leu Leu Ser Val Asp Lys Val Tyr
Val His Lys Lys Phe 275 280 285Val Pro Pro Lys Lys Ser Gln Glu Phe
Tyr Glu Lys Phe Asp Leu Val 290 295 300Ser Tyr Asp Tyr Asp Ile Ala
Ile Ile Gln Met Lys Thr Pro Ile Gln305 310 315 320Phe Ser Glu Asn
Val Val Pro Ala Cys Leu Pro Thr Ala Asp Phe Ala 325 330 335Asn Gln
Val Leu Met Lys Gln Asp Phe Gly Ile Val Ser Gly Phe Gly 340 345
350Gly Ile Phe Glu Arg Gly Pro Asn Ser Lys Thr Leu Lys Val Leu Lys
355 360 365Val Pro Tyr Val Asp Arg His Thr Cys Met Leu Ser Ser Asn
Phe Pro 370 375 380Ile Thr Pro Thr Met Phe Cys Ala Gly Tyr Asp Thr
Leu Pro Gln Asp385 390 395 400Ala Cys Gln Gly Asp Ser Gly Gly Pro
His Ile Thr Ala Tyr Arg Asp 405 410 415Thr His Phe Ile Thr Gly Ile
Val Ser Trp Gly Glu Gly Cys Ala Arg 420 425 430Lys Gly Arg Tyr Gly
Ile Tyr Thr Lys Leu Ser Lys Phe Ile Pro Trp 435 440
445Ile36455PRTNotechis scutatus 36Met Ala Pro Gln Leu Leu Leu Cys
Leu Ile Leu Thr Phe Leu Trp Ser1 5 10 15Leu Pro Glu Ala Glu Ser Asn
Val Phe Leu Lys Ser Lys Val Ala Asn 20 25 30Arg Phe Leu Gln Arg Thr
Lys Arg Ser Asn Ser Leu Phe Glu Glu Ile 35 40 45Arg Pro Gly Asn Ile
Glu Arg Glu Cys Ile Glu Glu Lys Cys Ser Lys 50 55 60Glu Glu Ala Arg
Glu Val Phe Glu Asp Asn Glu Lys Thr Glu Thr Phe65 70 75 80Trp Asn
Val Tyr Val Asp Gly Asp Gln Cys Ser Ser Asn Pro Cys His 85 90 95Tyr
Arg Gly Thr Cys Lys Asp Gly Ile Gly Ser Tyr Thr Cys Thr Cys 100 105
110Leu Pro Asn Tyr Glu Gly Lys Asn Cys Glu Lys Val Leu Tyr Gln Ser
115 120 125Cys Arg Val Asp Asn Gly Asn Cys Trp His Phe Cys Lys Arg
Val Gln 130 135 140Ser Glu Thr Gln Cys Ser Cys Ala Glu Ser Tyr Arg
Leu Gly Val Asp145 150 155 160Gly His Ser Cys Val Ala Glu Gly Asp
Phe Ser Cys Gly Arg Asn Ile 165 170 175Lys Ala Arg Asn Lys Arg Glu
Ala Ser Leu Pro Asp Phe Val Gln Ser 180 185 190Gln Lys Ala Thr Leu
Leu Lys Lys Ser Asp Asn Pro Ser Pro Asp Ile 195 200 205Arg Ile Val
Asn Gly Met Asp Cys Lys Leu Gly Glu Cys Pro Trp Gln 210 215 220Ala
Val Leu Ile Asn Glu Lys Gly Glu Val Phe Cys Gly Gly Thr Ile225 230
235 240Leu Ser Pro Ile His Val Leu Thr Ala Ala His Cys Ile Asn Gln
Thr 245 250 255Lys Ser Val Ser Val Ile Val Gly Glu Ile Asp Ile Ser
Arg Lys Glu 260 265 270Thr Arg Arg Leu Leu Ser Val Asp Lys Ile Tyr
Val His Thr Lys Phe 275 280 285Val Pro Pro Asn Tyr Tyr Tyr Val His
Gln Asn Phe Asp Arg Val Ala 290 295 300Tyr Asp Tyr Asp Ile Ala Ile
Ile Arg Met Lys Thr Pro Ile Gln Phe305 310 315 320Ser Glu Asn Val
Val Pro Ala Cys Leu Pro Thr Ala Asp Phe Ala Asn 325 330 335Glu Val
Leu Met Lys Gln Asp Ser Gly Ile Val Ser Gly Phe Gly Arg 340 345
350Ile Arg Phe Lys Glu Pro Thr Ser Asn Thr Leu Lys Val Ile Thr Val
355 360 365Pro Tyr Val Asp Arg His Thr Cys Met Leu Ser Ser Asp Phe
Arg Ile 370 375 380Thr Gln Asn Met Phe Cys Ala Gly Tyr Asp Thr Leu
Pro Gln Asp Ala385 390 395 400Cys Gln Gly Asp Ser Gly Gly Pro His
Ile Thr Ala Tyr Arg Asp Thr 405 410 415His Phe Ile Thr Gly Ile Ile
Ser Trp Gly Glu Gly Cys Ala Arg Lys 420 425 430Gly Lys Tyr Gly Val
Tyr Thr Lys Val Ser Arg Phe Ile Pro Trp Ile 435 440 445Lys Lys Ile
Met Ser Leu Lys 450 455378PRTHomo sapiens 37Asn Arg Phe Thr Lys Glu
Thr Tyr1 5
* * * * *